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Lumbar vertebral chordoma arising from an intraosseous benign notochordal cell tumour: Radiological findings and histopathological description with a good clinical outcome
Abstract
Benign notochordal cell tumours have recently been described as intraosseous benign lesions of notochordal cell origin. The lesions are found in vertebral bodies in 20% of autopsy studies and are a potential precursor of chordoma. We report a rare case of lumbar vertebral chordoma that was thought to arise from a benign intraosseous notochordal cell tumour and which showed significant osteosclerotic change. Radiologically, the lumbar vertebral mass lesion showed hyperintensity on T2 weighted images, with scanty enhancement on post-contrast T1 weighted MR images. High uptake corresponding to the mass was noted on fluorine-18-fluorodeoxyglucose positron emission tomography. Bone biopsy revealed proliferation of the physaliphorous cells between thickened bone trabeculae; no nuclear mitosis was observed. Although the mass was diagnosed clinically as spinal chordoma, histopathology contained both benign notochordal cell tumour and conventional chordoma. After heavy particle (11C)-charged radiation therapy was applied to the lesion with a sufficient radiation field margin, the tumour volume significantly decreased and there was improvement in the patient's symptoms. On follow-up radiological studies, the tumour had markedly regressed and there was no tumour regrowth or distant metastasis. In this case report, benign notochordal cell tumour and conventional chordoma are histopathologically identified in the L1 vertebral body, which contains osteosclerotic and osteolytic areas. It is suggested that the benign notochordal cell tumour coexists with a conventional chordoma and that this histopathological finding supports a hypothetical relationship between benign notochordal cell tumour and chordoma.
... Central to the discussion was the nature of the relationship, if any, between this benign-appearing tissue and chordoma. Several authors reported cases indicating an association between BNCT and chordoma [11][12][13][14][15][16] as others highlighted clear radiologic and histopathologic criteria for distinguishing between them [6][7][8][9][10]16,17]. ...
... Chordomas present as destructive, lytic lesions of bone on radiographs and CT, although intralesional calcification and varying radiodensity is reported [5,8,14,17,24]. Bony expansion may be seen. Bone scans demonstrate reduced or normal uptake [6,23]. ...
... Enhancement is common after contrast administration [14,16,17,24]. This tumor is slow-growing and progresses over time [6,8,17,23]. ...
Much discussion about benign notochordal cell tissue in vertebrae has centered on the nature of its relationship, if any, to chordoma. Often referred to as benign notochordal cell tumors (BNCTs), these lesions have unique morphological features, however, differentiating between notochordal cells in discs, BNCT, and chordoma can be difficult. They are described as radiologically distinct from chordoma, with lysis, contrast enhancement, and a soft tissue mass indicating chordoma.
All chordomas diagnosed at our institution, the Istituto Ortopedico Rizzoli (Bologna, Italy), prior to 2008 were reviewed, yielding 174 cases. Five were limited to bone; one was a recurrent chordoma without original data available. The remaining four were re-evaluated in detail.
There were three women and one man, aged 33-57 years (mean, 48 years). Two were BNCTs and two were mixed lesions containing BNCT and chordoma. On computed tomography, all were radiopaque with areas of lysis. One BNCT was heterogeneous on magnetic resonance imaging, enhancing after contrast. Microscopically, one BNCT had a well-defined cystic area with a sclerotic border. The other had a minute atypical area; it recurred as chordoma. The mixed lesions had areas of definitive BNCT, definitive chordoma, and atypical areas that did not meet the criteria for either. The atypical areas in all three cases 'blended' with areas of chordoma or BNCT.
These cases illustrate the ongoing challenges in differentiating between BNCT and chordoma. All had unique imaging features; three had atypical microscopic areas blending with BNCT or chordoma, strengthening the argument for a relationship between the two entities and supporting the idea that some BNCTs may progress to chordoma. Our study dispels the notion that any single radiologic criterion used to distinguish between chordoma and BNCT is reliable, opening the discussion as to whether or how to monitor BNCTs.
... La lésion ne se rehausse pas après injection de gadolinium [90]. Le développement de chordome à partir de cette tumeur bénigne a été rapportée [93]. 8.1.3.2.4.2. ...
... Park, en 2008[577], rapporte également un cas de chordome sacré chez une femme de 52 ans, détecté au 18 FDG-TEP-scan sous la forme d'une fixation hétérogène peu intense. Nishiguchi et al.[93] décrivent un cas de chordome associé à une BNCT fixant le 18 FDG et dont l'intensité a diminué après radiothérapie au 11 C. Ferraresi[578] mentionne que 2 des 10 patients traités par imatinib avaient une fixation initialement élevée, qui avait diminué sous traitement. Casali et al.[199] sont les seuls à présenter une série de 6 chordomes (5 sacrés et un clival) qui tous fixaient le 18 FDG lors du bilan initial. ...
To review in the literature, all the epidemiological, clinical, radiological, histological and therapeutic data regarding chordomas as well as various notochordal entities: ecchordosis physaliphora, intradural and intraparenchymatous chordomas, benign notochordal cell tumors, parachordomas and extra-axial chordomas. To identify different types of chordomas, including familial forms, associations with tuberous sclerosis, Ollier's disease and Maffucci's syndrome, forms with metastasis and seeding. To assess the recent data regarding molecular biology and progress in targeted therapy. To compare the different types of radiotherapy, especially protontherapy and their therapeutic effects. To review the largest series of chordomas in their different localizations (skull base, sacrum and mobile spine) from the literature.
... The latter case had identical imaging features to what we present, including location in the lower sacrum with a small associated soft tissue mass and pathological confirmation as a BNCT following complete surgical resection. In contradistinction, there is an additional case in the literature of a BNCT in the L1 vertebral body [16] with coexisting histologically proven chordoma forming a large epidural mass spanning two vertebral levels and causing compression of the conus medullaris. ...
... The remaining clinical and imaging features in our case are similar to previously reported BNCTs, including initial incidental detection with MRI, negative radiographs and subtle sclerosis on CT without evidence of a destructive osteolytic component. However, given the proposed theory by some authors that BNCT may represent a precursor lesion for chordoma, substantiated by the previously described case report of a lesion with coexistent BNCT and chordoma [16], this lesion will be followed closely with periodic MRI to ensure stability. ...
We report a case of a benign notochordal cell tumor (BNCT) of the sacrum with atypical imaging features,
which was incidentally discovered in a 74-year-old man undergoing evaluation for progressively worsening hip and back
pain. It is important for radiologists, pathologists and orthopedic surgeons to be aware of the diagnosis of BNCT and be
familiar with its radiographic features to avoid unnecessary treatment. This case illustrates the advantage of percutaneous
computed tomography (CT)-guided biopsy as a minimally invasive technique for definitive diagnosis of a BNCT with
atypical imaging features.
... BNCTs are well circumscribed but unencapsulated intraossous mass lesions with mild osteosclerosis and without bone destruction. 4 The patient's age in reported cases ranged from 11 to 57 years. [5][6][7][8] Notochordal rest is slightly more common in men than women. ...
... 11 Nishiquchi et al reported a chordoma case arising from a benign intraosseous notochordal cell tumor with a favorable post treatment outcome. 4 To our knowledge, this is the first reported case of intraosseous notochordal rest on touch preparation of a core biopsy. A touch preparation can provide diagnostic material. ...
Intraosseous notochordal rest is a rare intravertebral lesion of notochord origin which is presumably benign. It is usually an incidental finding in microscopic examination of vertebrectomy due to unrelated lesions or autopsy cases. Chordoma is a malignant neoplasm originating from notochord with a different clinicoradiographic presentation, prognosis, and treatment. However, the histology of intraosseous notochordal rest and chordoma is almost identical. Herein, we report cytomorphologic findings of a case of intraossous notochordal rest on touch preparation. Diagn. Cytopathol. 2014. © 2014 Wiley Periodicals, Inc.
... For cons, fine-needle aspiration biopsy is a procedure with low morbidity, which can convince our surgical colleagues and rheumatologists of the benign nature of these notochordal tumors. They also help to eliminate the rare cases where chordomas and benign notochordal tumors are associated, entangled in the same lesion [1]. ...
... Occasional locations of notochordal-rests are craniospinal-axis, sacrococcygeal, dorsum of sella and clival region 1, 2 Ecchordosis-physaliphora is rare benign gelatinous and hamartomatous tissue, typically situated intradurally and mostly attached to dorsal clivus through delicate pedicle. Rarely can be located 6,7 in sacrococcygeal region Intracranial location is within subdural and subarachnoid space in 2,8 prepontine cistern attached to dorsal clivus by pedicle and associated with bony defect 9,13,14 Usually asymptomatic due to small size and slow growth. Incidence~0.4-2% ...
A well defined 10 x 5.8 mm T2 hyperintense lesion which follows CSF signal intensity on all sequences seen in pre-pontine cistern to the left of basilar artery. Another similar lesion measuring 11.2 x 7.2 mm lesion seen to the right of midline in the pre pontine cistern. In all likelihood these two communicate in the midline. There are tiny T2 hyperintense lesions in the dorsal clivus similar in signal intensity to that of retroclival lesion. The retroclival lesion is connected to the dorsal clival lesions through a stalk.
... In rare cases, there are some reports that BNCT coexists with chordoma. Some reports suggested that BNCT may serve as a precursor lesion of chordoma [6][7][8][9]. In contrast, other investigators disagreed with this hypothesis because of little evidence [10]. ...
Key Clinical Message
Benign notochordal cell tumor is a benign intraosseous lesion, demonstrates characteristic imaging features. The lesion demonstrates low‐signal intensity in T1‐weighted images, high‐signal intensity in T2‐weighted images, and no enhancement with contrast medium in MRI and slight osteosclerosis in CT. If typical imaging findings are identified, biopsy is not necessary.
... A recent report Nouh MR et al . The normal spinal marrow: Magnetic resonance imaging the two entities [84] . MR imaging is the best modality to address and followup these lesions. ...
For now, magnetic resonance (MR) is the best noninvasive imaging modality to evaluate vertebral bone marrow thanks to its inherent soft-tissue contrast and non-ionizing nature. A daily challenging scenario for every radiologist interpreting MR of the vertebral column is discerning the diseased from normal marrow. This requires the radiologist to be acquainted with the used MR techniques to judge the spinal marrow as well as its normal MR variants. Conventional sequences used basically to image marrow include T1W, fat-suppressed T2W and short tau inversion recovery (STIR) imaging provides gross morphological data. Interestingly, using non-routine MR sequences; such as opposed phase, diffusion weighted, MR spectroscopy and contrasted-enhanced imaging; may elucidate the nature of bone marrow heterogeneities; by inferring cellular and chemical composition; and adding new functional prospects. Recalling the normal composition of bone marrow elements and the physiologic processes of spinal marrow conversion and reconversion eases basic understanding of spinal marrow imaging. Additionally, orientation with some common variants seen during spinal marrow MR imaging as hemangiomas and bone islands is a must. Moreover, awareness of the age-associated bone marrow changes as well as changes accompanying different variations of the subject's health state is essential for radiologists to avoid overrating normal MR marrow patterns as pathologic states and metigate unnecessary further work-up.
... Remnants of the notochord may give rise to chordoma and usually remain in or close to the midline, entrapped within bone (5). However, there are a number of reports that chordoma may develop from a benign notochordal cell tumor (6)(7)(8)(9). The tumor may occur at any age, but is usually observed in the fifth to seventh decades of life with male predilection (1). ...
Computed tomography (CT) and magnetic resonance imaging (MRI) scans of 11 patients with histologically proven cervical chordoma were retrospectively evaluated. Imaging features assessed included location, morphology, association with adjacent structures, vertebral destruction, status of cortical bone, periosteal reaction, attenuation and calcification by CT, and signal intensity and enhancement pattern by MRI. Of 7 cases with CT, 6 exhibited lytic-sclerotic bone destruction. A total of 5 cases exhibited pressure erosion of outer cortex, 3 of which had spiculated periosteal reaction. Calcification was observed in 3 cases. All cases were heterogeneous and hypodense. MRI T2-weighted images (n=10) revealed heterogeneous hyperintense (n=5), intermediate (n=2) and intermediate-hyperintense signal intensity (n=3). Hypointense septa between lobules (n=5) and stripes (n=3) were observed on T2-weighted images. Post-contrast magnetic resonance images (n=6) demonstrated marked heterogeneous (n=3) and ring-like (n=3) enhancement. CT scanning is valuable in revealing the lytic-sclerotic bone destruction, pressure erosion of outer cortex and calcification. MRI is useful in demonstrating the results of soft tissue mass. The two examinations are necessary for differential diagnosis of patients with suspected cervical chordoma.
... Benign notochordal cell tumour. These entities could be benign forms of chordoma [74]. Differential diagnosis is made on clinical and histological criterions [75]. ...
Paediatric chordomas are rare malignant tumours arising from primitive notochordal remnants with a high rate of recurrence. Only 5 % of them occur in the first two decades such less than 300 paediatric cases have been reported so far in the literature. In children, the average age at diagnosis is 10 years with a male-to-female ratio closed to 1. On the opposite to adults, the majority of paediatric chordomas are intracranial, characteristically centered on the sphenooccipital synchondrosis. Metastatic spread seems to be the prerogative of the under 5-year-old children with more frequent sacro-coccygeal locations and undifferentiated histology. The clinical presentation depends entirely on the tumour location. The most common presenting symptoms are diplopia and signs of raised intracranial pressure. Sacrococcygeal forms may present with an ulcerated subcutaneous mass, radicular pain, bladder and bowel dysfunctions. Diagnosis is suspected on computerised tomography showing the bone destruction and with typically lobulated appearance, hyperintense on T2-weighted magnetic resonance imaging. Today, treatment relies on as complete surgical resection as possible (rarely achieved because of frequent invasiveness of functional structures) followed by adjuvant radiotherapy by proton therapy. The role of chemotherapy has not been proven. Prognosis is better than in adults and depends on the extent of surgical resection, age and histology subgroup. Biological markers are still lacking to improve prognosis by developing targeted therapy.
... The patient in this study exhibited a normal gait according to the authors, 15 but other patients with chordoma present with abnormal gait or gait difficulties. 16,30 Gait kinematic analysis is a useful tool to evaluate the motor function of the hindlimbs in tumor-engrafted rats. 38 The stride length of the left hindlimb was affected 530 days after tumor engraftment; the right hindlimb had a compensatory role by supporting more weight during locomotion. ...
OBJECTIVE
Chordoma is a slow-growing, locally aggressive cancer that is minimally responsive to conventional chemotherapy and radiotherapy and has high local recurrence rates after resection. Currently, there are no rodent models of spinal chordoma. In the present study, the authors sought to develop and characterize an orthotopic model of human chordoma in an immunocompromised rat.
METHODS
Thirty-four immunocompromised rats were randomly allocated to 4 study groups; 22 of the 34 rats were engrafted in the lumbar spine with human chordoma. The groups were as follows: UCH1 tumor–engrafted (n = 11), JHC7 tumor–engrafted (n = 11), sham surgery (n = 6), and intact control (n = 6) rats. Neurological impairment of rats due to tumor growth was evaluated using open field and locomotion gait analysis; pain response was evaluated using mechanical or thermal paw stimulation. Cone beam CT (CBCT), MRI, and nanoScan PET/CT were performed to evaluate bony changes due to tumor growth. On Day 550, rats were killed and spines were processed for H & E–based histological examination and immunohistochemistry for brachyury, S100β, and cytokeratin.
RESULTS
The spine tumors displayed typical chordoma morphology, that is, physaliferous cells filled with vacuolated cytoplasm of mucoid matrix. Brachyury immunoreactivity was confirmed by immunostaining, in which samples from tumor-engrafted rats showed a strong nuclear signal. Sclerotic lesions in the vertebral body of rats in the UCH1 and JHC7 groups were observed on CBCT. Tumor growth was confirmed using contrast-enhanced MRI. In UCH1 rats, large tumors were observed growing from the vertebral body. JHC7 chordoma–engrafted rats showed smaller tumors confined to the bone periphery compared with UCH1 chordoma–engrafted rats. Locomotion analysis showed a disruption in the normal gait pattern, with an increase in the step length and duration of the gait in tumor-engrafted rats. The distance traveled and the speed of rats in the open field test was significantly reduced in the UCH1 and JHC7 tumor–engrafted rats compared with controls. Nociceptive response to a mechanical stimulus showed a significant (p < 0.001) increase in the paw withdrawal threshold (mechanical hypalgesia). In contrast, the paw withdrawal response to a thermal stimulus decreased significantly (p < 0.05) in tumor-engrafted rats.
CONCLUSIONS
The authors developed an orthotopic human chordoma model in rats. Rats were followed for 550 days using imaging techniques, including MRI, CBCT, and nanoScan PET/CT, to evaluate lesion progression and bony integrity. Nociceptive evaluations and locomotion analysis were performed during follow-up. This model reproduces cardinal signs, such as locomotor and sensory deficits, similar to those observed clinically in human patients. To the authors’ knowledge, this is the first spine rodent model of human chordoma. Its use and further study will be essential for pathophysiology research and the development of new therapeutic strategies.
... Unlike their malignant counterpart chordoma, BNCTs do not enhance and are not associated with osteolysis, vertebral collapse or soft tissue extension [6]. However, the coexistence of BNCT and chordoma has been described [8]. ...
... The microscopic examination of needle biopsies can help distinguish them [1]. In 2010, Nishiguchi [4] first described the histological association of BNCT-chordoma. Is there a filiation between these two lesions or is there a chance association? ...
... 1 Nowadays, notochordal tumors consist of 2 entities: BNCT and chordoma. It has been shown that at least some of the BNCTs are precursors of chordoma [2][3][4][5] (Fig. 1), although many textbooks and articles still state that ...
Recent molecular investigations of chordoma show common expression of various receptor tyrosine kinases and activation of downstream signaling pathways contributing to tumor growth and progression. The transcription factor brachyury (also known as T) is important in notochord differentiation and germline duplication of the gene is often found in familial chordomas. Nuclear expression of brachyury is consistent in chordoma and in benign notochordal cell tumor. Based on the molecular evidence, targeting of several kinds of molecular agents has been attempted for the treatment of uncontrolled chordomas and achieved partial response or stable condition in many cases.
To review in the literature, all the epidemiological, clinical, radiological, histological and therapeutic data regarding chordomas as well as various notochordal entities: ecchordosis physaliphora, intradural and intraparenchymatous chordomas, benign notochordal cell tumors, parachordomas and extra-axial chordomas. To identify different types of chordomas, including familial forms, associations with tuberous sclerosis, Ollier's disease and Maffucci's syndrome, forms with metastasis and seeding. To assess the recent data regarding molecular biology and progress in targeted therapy. To compare the different types of radiotherapy, especially protontherapy and their therapeutic effects. To review the largest series of chordomas in their different localizations (skull base, sacrum and mobile spine) from the literature.
Chordomas are malignant tumors of the axial skeleton, characterized by their locally invasive and slow but aggressive growth. These neoplasms are presumed to be derived from notochordal remnants with a molecular alteration preceding their malignant transformation. As these tumors are most frequently observed on the skull base and sacrum, patients suffering from a chordoma present with debilitating neurological disease, and have an overall 5-year survival rate of 65%. Surgical resection with adjuvant radiotherapy is the first-choice treatment modality in these patients, since chordomas are resistant to conventional chemotherapy. Even so, management of chordomas can be challenging, as chordoma patients often present with recurrent disease. Recent advances in the understanding of the molecular events that contribute to the development of chordomas are promising; the most novel finding being the identification of brachyury in the disease process. Here we present an overview of the current paradigms and summarize relevant research findings.
To report 2 rare cases of benign notochordal cell tumor (BNCT), according to WHO classification of tumors of soft tissue and bone (4th edition). Their radiologic and clincopathologic features and differential diagnosis were investigated.
Two cases of BNCT were studied by retrospective review of the clinical, radiologic, pathologic and immunophenotypical findings. Related literatures were reviewed at the same time.
Case 1 was a 53-year-old man, and case 2 was a 61-year-old woman. Radiographically, both patients presented with abnormal imaging findings in the fifth cervical vertebral body with the lesions located within the bone but without extra osseous mass. Histopathologically, the lesions lacked lobular architecture and extracellular myxoid matrix. The tumor cells were vacuolated and had centrally or peripherally placed round or oval nuclei with small nucleoli, mimicking mature adipocytes. No cytological atypia or mitotic figures were seen. The affected bone trabeculae were sclerotic and islands of bone marrow were often entrapped within the tumor.
Although sharing similar anatomic distribution and immunophenotype to those of chordoma, BNCT has distinct radiologic and pathologic features and different treatment and prognosis. The differential diagnosis between BNCT and chordoma requires detailed clinical, radiologic and histopathologic evaluations.
Although rare, chordomas can affect the entire axial skeleton, and they are the most common primary malignant bone tumor in both the sacrum and the spine. This article details tumor origin, epidemiology, pathology, and imaging features, in an effort to improve the ability of the radiologist to diagnose, provide a differential diagnosis, and further understand treatment of patients with chordomas.
Chordoma is a rare malignant tumor of the bone; it arises from embryonic remnants of the primitive notochord and occurs along the midline from the skull base to the sacrum. In this article, we reviewed the origin, location, clinical, histopatological and imaging features, treatment, and differential diagnosis of chordoma.
Chordomas are rare tumors in the craniospinal axis arising from persistent notochordal rests commonly seen in the skull base, including the clivus and the sacrum. Chordomas in the mobile spine occur less commonly. To the best of our knowledge, the clinical presentation of acute cauda equina syndrome (CES) due to chordoma of the lumbar vertebra is not published in the English literature.
To describe an unusual cause of acute CES resulting from chordoma of the lumbar vertebra and discuss management dilemmas in this clinical context.
Case report with review and discussion.
We report the case of a 75-year-old man who presented with acute CES that was clinically considered a metastasis from his previously documented carcinoma of the urinary bladder treated a year ago. Clinical, radiological, and histopathological features of the case and a review of chordomas in the lumbar vertebrae in adults in the published English literature are presented.
He underwent urgent surgical decompression with laminectomy of L3/L4 and L4/L5 with debulking and open biopsy of the tissue mass. Histopathological examination of the tissue mass confirmed the unsuspected diagnosis of chordoma. The salient features of chordomas in the lumbar vertebrae published in the English literature over the last 22 years are summarized. The origin, classification, clinical presentation, and management protocols for lumbar chordomas are also reviewed.
The clinical presentation of acute CES as the first symptom of chordoma in the lumbar vertebrae is extremely rare. Preoperative tissue diagnosis of this uncommon pathology is usually unavailable. In the face of acute CES, surgical decompression remains the primary goal of management with a planned definitive second-stage curative surgical resection for chordoma.
Background:
Notochord-related lesions of the spinal column include benign notochordal cell tumors (BNCTs), ecchordosis physaliphora, both generally considered benign lesions, and chordomas, which represent malignant tumors. The histological similarity of these lesions to the notochord and each other and their strong predilection to the axial skeleton have led to the hypothesis that these lesions represent a continuum of malignant transformation from notochordal remnants, BNCTs, and finally chordomas.
Objective:
To present a cohort of biopsy-proven BNCTs with a description of radiographic features, histology, and follow-up to help elucidate the optimal management of these lesions.
Methods:
A retrospective chart review identified 13 patients with notochordal rest lesions confirmed by histology. Histologic inclusion criteria included notochordal features without evidence of septation, myxoid matrix, nuclear atypia, or mitotic figures. Tumors exhibiting evidence of cortical expansion or destruction were excluded. The natural history and histological and radiographic features were examined.
Results:
Sixteen spinal lesions from 8 patients met the diagnostic criteria for BNCTs, identified on imaging after the patient presented with back pain. Radiographically, all lesions were hypointense on T1-weighted magnetic resonance imaging sequences and hyperintense on T2-weighted and short T1 inversion recovery. The median radiographic follow-up was 21.6 months (range, 8.5-71.2 months). None of the lesions exhibited radiographic or symptomatic progression.
Conclusion:
Although limited by short follow-up, our series confirms that these lesions may be safely observed without evidence of malignant transformation, which emphasizes the importance of distinction of BNCT from chordoma at diagnosis and the possibility of close follow-up for these lesions instead of aggressive treatment indicated in patients with chordomas.
Solitary vertebral chordoma presents as an intra- and extraosseous tumour with typical bright signal on T2-weighted images and moderate inhomogeneous enhancement on T1 postcontrast images. The diffusion weighted imaging (DWI) characteristics of this histologically proven third lumbar vertebra chordoma are reported for the first time. The DWI hyperintensity with increased apparent diffusion coefficient (ADC) values strongly supports the preoperative diagnosis of a vertebral chordoma, allows for careful preoperative planning of the surgical procedure, and helps to narrow the differential diagnosis.
Benign bone tumors frequently pose a diagnostic challenge for general surgical pathologists. Accurate pathologic diagnosis requires careful clinical and radiological correlation. The most significant recent advances in some benign bone tumors have occurred at the molecular and cytogenetic level. The detection of clonal chromosomal aberrations, various specific molecular genetic events, and the description of the bone cell signaling pathways in the field of osteoimmunology have provided a better understanding of the pathophysiology of certain tumors and an important aid in the diagnostic workup and differential diagnosis of some bone lesions demonstrating overlapping clinical and pathologic features. Future directions include prognostic and therapeutic applications of these findings. Newer less invasive therapeutic techniques and medical management have been developed for the treatment of certain benign bone tumors.
Chordomas are extra-axial, low-grade malignancies growing slowly, located anywhere from the clivus to the sacrum on the axial skeleton. Grossly they are unencapsulated, usually lobulated, pink-gray colored, invasive tumors with foci of hemorrhage and calcifications exhibiting epithelial phenotype. Histopathologically they are classified as classic chordomas, chondroid chordomas, and atypical chordomas. Classic chordomas are characterized by the presence of physaliferous cells which are large, vacuolated, mucus-containing cells with hyperchromatic, eccentric nuclei having prominent nucleoli rarely demonstrating atypia and reticulated cytoplasm due to intracellular accumulation of glycosaminoglycans, similar to the cells of notochord. The cytoplasm is eosinophilic and stains positive with the periodic acid Schiff stain. Other cell types are stellate cells and intermediate or transitional cells.
Introduction:
Brain notochordal cell tumors (BTCN) are lesions arising from notochordal differentiation which affect the axial skeleton.
Presentation of case:
We report a case of a patient treated in our General Surgery Unit of the University Hospital of Bari, Italy, with occasional finding of sacral chordoma at the histological examination.
Discussion:
Because of their location, sacral chordomas can affect bowel and bladder with organ specific symptoms. Radiotherapy may be used as a palliative treatment or for recurrence in those patients who cannot be submitted to surgery.
Conclusions:
Due to the high local recurrence rate radiation therapy should be considered mandatory after any type of chordoma resection. Multidisciplinary management of the disease is mandatory and improve patient outcomes. Patients should have maximal tumor debulking with adjuvant radiotherapy when possible.
Chordoma is a notochord-derived primary tumor of the skull base and vertebral column known to affect 0.08-0.5 per 100,000 persons worldwide. Patients commonly present with mechanical, midline pain with or without radicular features secondary to nerve root compression. Management of these lesions has classically revolved around oncologic resection, defined by en bloc resection of the lesion with negative margins as this was found to significantly improve both local control and overall survival. With advancement in radiation modalities, namely the increased availability of focused photon therapy and proton beam radiation, high-dose (>50Gy) neoadjuvant or adjuvant radiotherapy is also becoming a standard of care. At present chemotherapy does not appear to have a role, but ongoing investigations into the ontogeny and molecular pathophysiology of chordoma promise to identify therapeutic targets that may further alter this paradigm. In this narrative review we describe the epidemiology, histopathology, diagnosis, and treatment of chordoma.
Ependymoma and chordoma are 2 tumors that occur throughout the craniospinal axis, and for which the extent of neurosurgical resection has a key prognostic role. Both tumors have distinctive pathologic features, yet can present significant diagnostic challenges to pathologists in cases without classical histology. The molecular understanding of ependymoma has had significant advances in the past decade, with the identification of 9 molecular groups with significant prognostic and clinical implications, while a comprehensive study of chordoma further emphasized the key role of brachyury overexpression in its pathogenesis. In this review, we discuss the pathogenesis, radiology and gross pathology, histology, and molecular features of these 2 tumors, as well as active research into targeted therapies, with an emphasis on practical diagnostic challenges, and the use of immunohistochemical and molecular tests in routine diagnostic practice.
Benign notochordal tumor is a benign, indolent bone tumor probably derived from vestigial notochordal rests. As it is usually asymptomatic, its true incidence is unknown; it has been found in 20% of spines in an autopsy study. Radiographs, CT, or bone scan may appear normal. MRI shows altered signal intensity. Histologically, it appears as a sheet-like proliferation of bland-looking cells with a well-defined boundary, resembling fatty marrow at low magnification, immunohistochemically positive for S100, epithelial markers, and brachyury. Foci of chordoma may be found next to the lesion, suggesting a histogenetic relationship; several authors have reported cases of chordoma arising from a benign notochordal cell tumor. Surgery is indicated only for large lesions and for differential diagnosis.
The integration of clinical, radiographic and pathology-based information has long been intrinsic to practice of Orthopaedic Oncology, making it paradigm of multidisciplinary medicine. Extension of this multifactorial approach can lead to better understanding of heterogeneous group of entities. Historically, pathologists have approached the study of bone tumors from imaging to gross to histological findings. However, a reversal of this norm emphasizing a detailed understanding of the histopathology and growth parameters of each entity can allow a better understanding of the macroscopic / gross appearance of the orthopaedic tumors which in turn leads to a better appreciation of the imaging features. The chapter emphasizes those tumors most unique to bone: cartilage, osseous, small cell, fibrous, vascular, notochord, adamantinoma and giant cell lesions.
Background:
There are no absolute defining criteria for benign notochordal cell tumors; the diagnosis is usually based on small size and the absence of aggressive features. Therefore, by definition, the diagnosis is subjective and usually determined by multidisciplinary consensus. A benign notochordal cell tumor should not grow during surveillance, and this may be used to confirm the diagnosis, but is a tautologic definition. Diagnostic ambiguity leads to uncertainty in management. If a tumor is a small chordoma then early surgery is likely to provide a better outcome. However, unnecessary treatment of a benign tumor may incur unjustified risk.
Objective:
To propose clearer guidelines for the definition and management of benign notochordal tumors.
Methods:
We performed a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) review of the reported definitions for benign notochordal tumors and their management.
Results:
The accepted features of benign notochordal tumors vary considerably: a typical tumor may be diagnosed in the absence of neurology, radiologically well-corticated bony margins, size <35 mm, no enhancement with contrast, no soft tissue extension, no dural penetration, no progression on scans, histologic absence of extracellular myxoid matrix, and low Ki67 index. If these criteria are fulfilled, it is reasonable to use radiologic surveillance in the first instance. Biopsy may be offered depending on the relative risks of performing the biopsy, or if there are atypical features.
Conclusions:
We suggest a clearer definition for a benign notochordal tumor and a management algorithm that incorporates a level of diagnostic uncertainty.
Aims
To study the clinicopathological and molecular features of benign notochordal cell tumours (BNCTs) and their differential diagnosis from chordoma.
Methods
13 cases of BNCT were investigated. The genome-wide copy number imbalances were performed using Oncoscan CNV array in three cases and fluorescence in situ hybridisation (FISH) detection of epidermal growth factor receptor (EGFR)/chromosome 7 enumeration probe (CEP7), LSI1p36/1q21, LSI19p13/19q13, CEP3/CEP12 and Telvysion 6 P was performed in 13 cases.
Results
All 13 BNCTs were symptomatic and eight cases showed a close relationship with the bones of the skull base. The important histological character for differential diagnosis with chordoma was the absence of extracellular matrix and eosinophil cells and the presence of vacuoles in most tumour cells. Immunohistochemical staining of AE1/AE3, vimentin, epithelial membrane antigen, S-100 and brachyury (100% each) were positive in BNCTs. Gain of chromosome 7 occurred in 10 cases (76.9%), gain of 1p in four (30.8%), gain of 1q in five (38.5%), gain of 19p and 19q in five (38.5%), gain of chromosome 12 in 11 cases (84.6%), gain of 6p in eight (61.5%) and gain of chromosome 3 in four cases (30.8%).
Conclusions
In contrast to chordoma, chromosome gain or normal copy number was more common while chromosome loss was infrequent in BNCTs. This may be a differential diagnosis clue for chordoma and may be an important characteristic in the progression of notochordal cell tumours.
Benign notochordal tumor is a benign indolent bone tumor probably derived from vestigial notochordal rests. As it is usually asymptomatic, its true incidence is unknown but has been found in 20 % of spines in an autopsy study. Radiographs, CT, or bone scan may appear normal. MRI shows altered signal intensity. Histologically, it appears as sheet-like proliferation of bland-looking cells with well-defined boundary, resembling fatty marrow at low magnification. Foci of chordoma may be found next to the lesion, suggesting histogenetic relationship. It is immunohistochemically positive for S100, epithelial markers, and brachyury. Surgery is only indicated in large lesions and for differential diagnosis.
This case reports a 25-year-old woman initially diagnosed with adjacent benign notochordal cell tumors (BNCTs) of L3 and L4 based on needle biopsy of L3 and stable imaging over a 3-year period who was ultimately found to have a chordoma arising from a BNCT at L3. It illustrates the potential relationship between benign and malignant notochordal tumors and the difficulty in distinguishing them by clinical, radiological, and even histopathological means.
Purpose:
To describe the imaging and clinical characteristics of chordoma osseous metastases (COM).
Materials and methods:
Our study was IRB approved and HIPAA compliant. A retrospective search of our pathology database for pathology-proven COM yielded 15 patients who had undergone MRI, CT, bone scan, and/or FDG-PET/CT. The imaging and clinical features of the COMs were recorded. A control group of age and gender matched chordoma patients without osseous metastasis was evaluated.
Results:
The COM mean maximal dimension was 6.4 ± 4.0 cm. The majority (60%) of patients had one lesion. Extra-osseous soft tissue component was present in 85% and was larger than intra-osseous component in 76%. On MRI the lesions were heterogeneous but predominantly T2 hyperintense with hypointense septae, and with variable enhancement. On CT the lesions were typically destructive or permeative; calcifications were rare. The extent of the soft tissue component was isodense to muscle on CT and therefore better evaluated on MRI. COM was in a body part contiguous to the site of the primary tumor. Compared to the controls, COM patients were more likely to have local recurrence (P = 0.0009) and positive resection margins (P = 0.002). At 1 year, 33% of COM patients were deceased and 13% had progressive metastases.
Conclusion:
COM are associated with large extra-osseous soft tissue components, which are better visualized by MRI. They are often located in a body part contiguous to the site of the primary tumor, portend poor prognosis, and are associated with positive resection margins and local recurrence.
Study designCase report. PurposeWe present a rare case of a giant chordoma in the thoracolumbar spine and review the current literature. We describe its complicated clinical progression, hoping to shed light on the clinical management of this complex tumor. Methods
We present a previously healthy 41-year-old man who experienced progressive low back pain at T10-L2 for the past 2 years. A giant tumor was detected on magnetic resonance imaging, and aspiration biopsy was used to obtain a definite pathological diagnosis. The postoperative pathology confirmed that it was a chordoma. He underwent complete resection of the tumor and internal fixation of the vertebral bodies, which is a good way to control recurrence and preserve stability. ResultsHistopathology confirmed the tumor was a chordoma via immunohistochemical study of both the biopsy sample and the surgically resected tissues. There has been no recurrence or metastasis at the 30-month postsurgery radiographic examination. The internal fixation has remained stable. Conclusion
Primary chordoma in the thoracolumbar spine is extremely rare. The treatment is difficult because the current literature is sparse and patients are rare. Complete resection and internal fixation are effective for reducing recurrences and metastasis.
By the current WHO classification, benign notochordal cell tumor (BNCT) and chordoma comprise the entire spectrum of notochordal-derived tumors. They have defined radiologic and histologic criteria, and differ considerably in management and clinical outcome. Chordomas are malignant tumors; they show progressive, destructive growth and have the capacity for metastasis. In contrast, BNCT are benign and show limited intraosseous growth. Patients with BNCT can be managed with serial imaging or conservative excision, whereas patients with spinal/sacral chordomas typically undergo radical en bloc resection often with adjuvant therapy and significant morbidity. As such, the distinction between BNCT and chordoma is critically important. We have seen 4 unusual notochordal tumors with radiologic and/or histologic features that defy classification as either BNCT or chordoma. Cases occurred in 4 adults (53 to 83 y), and involved the lumbar spine (N=2) and sacrum (N=2). Three cases had subtle radiologic features of cortical permeation with minimal soft tissue extension. All 4 cases had the characteristic histologic features of BNCT; however, 2 cases also had focal myxoid change. Three patients were followed with serial imaging (follow-up range, 26 to 120 mo); 2 showed no disease progression and 1 had a 10-year cumulative interval growth of 3.7 mm. One patient underwent sacrectomy. The tumor was examined in toto and had the characteristic histologic features of BNCT, with the exception of minimal soft tissue extension. On the basis of these observations, we propose a provisional designation of atypical notochordal cell tumors (ANCT) be used for the subset of notochordal-derived tumors that fail to fulfill current diagnostic criteria for either BNCT or chordoma. We would argue that designating these atypical notochordal tumors as chordoma precipitates potentially overly aggressive surgical management. Patients with ANCT may be better managed by close observation and serial imaging. Additional studies with more cases and longer clinical follow-up should clarify the relationship of ANCT to BNCT and chordoma.
Benign bone lesions may occasionally be incidentally detected on radiographs and are also increasingly found on computed tomography or magnetic resonance imaging performed for other clinical indications. Although mostly asymptomatic or associated with minor symptoms, these lesions may simulate true pathological lesions, causing problems in diagnosis. For instance, asymptomatic benign bone lesions can be misinterpreted as metastasis when incidentally encountered in a patient with known cancer. Recognizing these entities as “do-not-touch” lesions helps avoid unnecessary further investigation or harmful intervention. In this review, we highlight three groups of bone incidentalomas found in adults, namely: osteolytic lesions, osteoblastic lesions, and bone protuberances. We aim to review the key imaging features of selected common and less common conditions in these three groups, so as to help radiologists confidently identify these benign do-not-touch lesions and to distinguish them from more sinister pathological lesions.
The purpose of this study was to characterize the imaging spectrum of benign notochordal cell tumors (BNCTs) and chondromas and to determine if this helped in differentiating BNCTs from chordomas.
Thirty-eight patients pathologically diagnosed with chordomas were reviewed and ultimately diagnosed to have five BNCTs and 33 chordomas. The following radiologic findings were reevaluated by two radiologists by consensus: extraosseous extension, osseous change on CT or conventional tomography, T2-weighted MR signal intensity, T2-weighted signal homogeneity, and contrast-enhanced T1-weighted MR signal intensity. Fisher's exact test was performed to determine statistical significance.
Our study yielded five results. First, four of five BNCTs (80%) were intraosseous, whereas 31 of 33 chordomas (94%) were both intra- and extraosseous (p < 0.0001). Second, all BNCTs showed mild osteosclerosis without bone destruction; all chordomas showed variable osteolysis (p = 0.0092). Third, all BNCTs and 28 of 33 chordomas (85%) showed hyperintensity on T2-weighted images (p > 0.05). Fourth, four of five BNCTs (80%) and 27 of 33 chordomas (82%) were heterogeneous on T2-weighted images (p > 0.05). Fifth, no BNCTs enhanced, whereas all chordomas variably enhanced (p < 0.0001).
Radiologic studies may allow distinction of BNCTs from chordomas.
The objective was to characterize imaging findings of benign notochordal cell tumors (BNCTs).
Clinical and imaging data for 9 benign notochordal cell tumors in 7 patients were reviewed retrospectively. Conventional radiographs (n = 9), bone scintigrams (n = 2), computed tomographic images (n = 7), and magnetic resonance images (n = 8) were reviewed. Eight of the 9 lesions were stained with hematoxylin-eosin and microscopically examined.
There were 3 male and 4 female patients with an age range of 22 to 55 years (average age, 44 years). Two patients had two lesions at different sites. The lesions involved the cervical spine in 4 patients, the lumbar spine in 2, the sacrum in 2, and the coccyx in 1. The most common symptom was mild pain. The lesions of 2 patients were found incidentally during imaging studies for unrelated conditions. Five patients underwent surgical procedures. One patient died of surgical complications. All other patients have been well without recurrent or progressive disease for 13 to 84 months. Radiographs usually did not reveal significant abnormality. Five lesions exhibited subtle sclerosis and 1 showed intense sclerosis. Technetium bone scan did not reveal any abnormal uptake. Computed tomography images had increased density within the vertebral bodies. The lesions had a homogeneous low signal intensity on T1-weighted magnetic resonance images and a high intensity on T2-weighted images without soft-tissue mass. Microscopically, lesions contained sheets of adipocyte-like vacuolated chordoid cells without a myxoid matrix.
Benign notochordal cell tumors may be found during routine clinical examinations and do not require surgical management unless they show extraosseous disease. These tumors should be recognized by radiologists, pathologists, and orthopedic surgeons to prevent operations, which usually are extensive.
Chordoma is an uncommon primary bone tumor and the thoracic spine is the least common of all sites for a chordoma. It may recur despite slow-growing nature. Precise literature review will be performed and possible use of fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) for detection of both primary and recurrent diagnosis will be discussed. This article presents the case of a 73-year-old male patient who complained of back pain. Magnetic resonance (MR) imaging, computed tomography (CT) and FDG-PET demonstrated thoracic lesion and biopsy revealed chordoma. The patient was operated on and histological findings showed the tumor was chondroid chordoma. He suffered recurrence after 7 months by FDG-PET. He received 6,000 rads radiation therapy and is neurological free but, suffered backache 15 months after initial diagnosis. Only 12 cases including this case were reported precisely and this is the first report of FDG-PET for both initial and recurrent diagnosis of chordoma.
A microscopic ectopic remnant of notochord and hyaline cartilage was an incidental autopsy finding within a vertebral body. Such ectopic notochordal vestiges have been hypothesized to be the origin of vertebral chordomas, but very few have ever been reported. Whereas ectopic notochord has been demonstrated regularly in the spheno-occipital region (in both embryos and adults) and in the sacrococcygeal region (in embryos), the occurrence of such tissue rests in other segments of the vertebral column is extremely rare. The possible relationship of ectopic vertebral notochordal rests to associated hyaline cartilage formation and to vertebral chordomas requires further investigations.
Chordomas of the lumbar vertebral bodies are rare. We report an unusual case of an entirely intraosseous chordoma of the fifth lumbar vertebra treated by vertebrectomy. Conventional radiographs and scintigraphy were normal. The lesion was well visualised by MR imaging, but showed only slight sclerosis on CT. We give our reasons for making a diagnosis of chordoma rather than giant notochordal rest and discuss the problems of management resulting from this diagnostic dilemma.
The first histologically confirmed case of a classic chordoma arising in a precursor benign notochordal lesion is presented and the differential diagnosis between benign and malignant notochordal lesions is discussed. A 57-year-old man presented with a classic chordoma in the coccyx. The resected specimen demonstrated a small intraosseous benign notochordal lesion in the coccyx, which was adjacent to the classic chordoma. Also seen were two separate, similar benign lesions in the sacrum. The classic chordoma consisted of multiple lobules that were separated by thin fibrous septa and that showed cords or strands of atypical physaliphorous cells set within an abundant myxoid matrix. In contrast, the benign lesions consisted of intraosseous sheets of bland physaliphorous cells without any extracellular matrix. The affected bone trabeculae showed sclerotic reactions. It was concluded that benign and malignant notochordal lesions can be distinguished microscopically.
Intraosseous benign notochordal cell tumors are recently recognized conditions that may undergo malignant transformation to classic chordomas. This study attempts to define the morphologic and immunohistochemical characteristics of 34 benign notochordal cell tumors by contrasting them with classic chordomas and the notochordal vestiges in fetal intervertebral discs. Benign notochordal cell tumors were characterized by well-demarcated though unencapsulated sheets of adipocyte-like vacuolated and less vacuolated eosinophilic cells within axial bones. The round nuclei were mildly polymorphic but bland. The tumor cells often contained cytoplasmic eosinophilic hyaline globules and lack any intercellular myxoid matrix or necrosis. The involved bone trabeculae were often sclerotic without evidence of bone destruction. The histologic features were different from those of both notochordal vestiges in fetal intervertebral discs and classic chordomas. There was overlap in immunohistochemical reactivity of benign notochordal cell tumors and chordomas, but notochordal vestiges failed to demonstrate cytokeratin 18 positivity. A more appropriate term for the lesions is "benign notochordal cell tumor" rather than "notochordal rest" or "notochordal hamartoma" as they are not rests and do not fulfill the definition of hamartoma. Benign notochordal cell tumors do not need any surgical procedure and must be adequately recognized to prevent unnecessary operations.
Intraosseous benign notochordal cell tumour is a recently recognized condition that may undergo malignant transformation to classic chordoma. The aim of this study was to describe its clinicopathological characteristics.
One hundred vertebral columns from atlas to coccyx and 61 pieces of the clival portion of the skull base, which were dissected from 100 autopsy cases, were examined microscopically. Twenty-six intraosseous benign notochordal cell tumours were found in 20 cases. The patient group consisted of 15 males and five females with a mean age of 63 years. The results, according to anatomical segments, showed that 11.5% of the clivus, 5.0% of the cervical vertebrae, 0% of the thoracic vertebrae, 2.0% of the lumbar vertebrae, and 12.0% of the sacro-coccygeal vertebrae were affected. Microscopic examination revealed well demarcated but unencapsulated sheets of bland physaliphorous cells mimicking adipocytes. The lesions lacked any intercellular myxoid matrix. The affected bone trabeculae were characteristically sclerotic.
The study indicated a surprisingly high incidence of intraosseous benign notochordal cell tumours. The anatomical distribution of the tumours was identical to that of classic chordomas. The results support other evidence that classic chordomas develop from intraosseous benign notochordal cell tumours.
A consecutive series of 52 chordomas of the mobile spine observed over a 50-year period includes a retrospective review of 15 cases treated prior to 1991 and a prospective group of 37 cases treated from 1991 to 2002.
This series reviews epidemiologic issues as well as clinical patterns of spinal chordomas. We attempt to correlate tumor extent, treatment, and outcomes over time.
Chordoma is the most frequent primary tumor of the mobile spine. Due to slow growth, both initial symptoms and recurrences after treatment arise later, making it difficult to evaluate the effectiveness of treatment protocols.
A prospective series of 37 cases is compared with a retrospective group of 15 patients observed between 1954 and 1991. In the prospective study, all patients had imaging studies, and oncologic and surgical staging. When en bloc resection was not feasible, intralesional extracapsular excision was combined with radiation therapy. The prospective patients were clinically evaluated and imaged. Patients in the retrospective group were evaluated by chart and available images; of these, only one en bloc resection (intralesional margin) was performed. Survivors were all evaluated clinically and had radiographic studies.
Forty-eight patients were available for long-term follow-up. Four died due to post-operative complications, and six due to disease less than 2 years after treatment. Forty-two patients were followed over 2 years; 26 patients had over 5 years follow-up. All patients having radiation alone, intralesional excision, or a combination had recurrences in less than 2 years, and died in some cases after a long survival with symptomatic disease. Intralesional extracapsular excision with radiation had a high rate of recurrence (12 of 16 at average 30 months), but 3 patients are continuously disease-free (CDF) at mean 52 months and 5 are alive with disease at average 69 months (ranging 24 to 146). Twelve of 18 patients having en bloc resection are CDF at average 8 years (48 to 155 months). The remaining 6 recurred and of these 1 died. All of these (6) had been previously treated and/or had en bloc resections with contaminated margins.
The only treatment protocol associated with CDF at follow-up longer than 5 years is margin-free en bloc resection.
Case report.
To present a rare case of a notochordal cell tumor.
We report on a 27-year-old female patient with pain at the lower back and muscle cramps in the area of the right hip. Image studies demonstrated a cystic lesion of the coccyx.
As clinical symptoms became chronic and were resistant to conservative treatment, a resection of the coccyx was performed.
Histology revealed an intraosseous benign notochordal cell tumor. This tumor represents a recently described notochordal cell proliferation biologically distinct from chordomas.
Overdiagnosis of these notochordal cell proliferations as chordomas may occur if clinicians and pathologists are unfamiliar with the spectrum of notochordal proliferations.
Previous studies have documented the existence of intraosseous benign notochordal cell tumors (BNCTs) within the axial skeleton. Evidence suggests that they may be associated with the development of chordomas. To further investigate the relationship between BNCT and classic chordoma, we reviewed a large series of resected sacral/coccygeal chordomas in an attempt to identify the presence of coexisting BNCTs.
Eighty-two sacrectomy/coccygectomy specimens performed for chordoma were identified. Available hematoxylin and eosin slides were reviewed to identify BNCTs and assess their relationship with the coexisting chordoma. BNCTs were defined, in accordance with prior descriptions, as cohesive aggregates of large cells that appeared adipocyte-like because of their vacuolated cytoplasm. The cells exhibited only minimal nuclear atypia and lacked lobulation and myxoid stroma.
We identified 6 BNCTs, each was adjacent to but separate from the sacral chordoma. There were 5 females and 1 male, and the mean age was 58 years. Five lesions arose in the sacrum. One lesion arose in the coccyx, and involved 2 contiguous vertebral levels. The BNCTs ranged in size from 1 to 20 mm with a mean size of 6.1 mm. The lesions were exclusively composed of adipocyte-like nuclei without significant nuclear atypia or myxoid stroma. Three lesions contained sclerotic bony trabeculae and intralesional hematopoietic elements were identified in 1 case. In all cases the chordoma was of the conventional type and were morphologically different from the BNCT.
BNCTs were identified in 7.3% of sacral/coccygeal resections performed for primary chordoma. We speculate that this finding provides further evidence that BNCT is the precursor lesion for chordoma. Additional investigations are needed to further understand this relationship.
Nontumoral notochordal inclusions in vertebral bone marrow give rise to MRI-detectable lesion without osteolysis, and their detection may cause concern or overtreatment. These lesions likely arise from dislocation of notochordal cells from the nucleus pulposus early in life, followed by growth in a permissive bone marrow microenvironment. We present a case of nontumoral notochordal inclusions in vertebral bone marrow, giving rise to an MRI detectable lesion without osteolysis. MRI detection of such lesions may cause concern or overtreatment. Quite distinct from chordomas, these lesions likely arise from dislocation of notochordal cells from the nucleus pulposus early in life, followed by growth in a permissive bone marrow microenvironment.