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Localized fibrous tumors of pleura: A light and electron microscopic study
Abstract
Light and electron microscopic studies of two localized fibrous tumors of pleura are presented. The tumors showed microscopically a purely fibrous character without preformed slit-like spaces, or papillary or tubular structures. The neoplasms were encapsulated, pedunculated, and projected freely into the pleural cavity. Fine structural studies showed fibroblasts with prominent rough endoplasmic reticulum, intracytoplasmic bundles of fibrils, and elongated cytoplasmic processes. Desmosomes, microvilli, or basement membrane-like material was not observed. Although fibrous tumors of pleura are generally regarded as mesotheliomas, there are those in which the cell components are purely fibroblastic in nature, without light microscopic or ultrastructural resemblance to mesothelial cells. They derive probably from fibroblasts normally present underneath the visceral pleura, as suggested by the presence of a fibrous capsule covered by an intact mesothelial cell lining. It is proposed to name those neoplasms “localized fibrous tumors of pleura,” without implying their mesothelial origin unless mesothelial cells are demonstrated within the tumor tissue. Encapsulated fibrous tumor of pleura are usually benign and adequately treated by local excision.
... They have been historically recognized by several names, including benign mesothelioma, pleural fibroma, subserosal fibroma, solitary fibrous mesothelioma, submesothelial fibroma, and localized fibrous tumors [1]. Advancements in microscopy and immunohistochemistry proved instrumental in pinpointing that the origin of this tumor from the submesothelial, noncommitted mesenchymal layer, and not from the mesothelial layer [2]. Therefore, now this entity is referred to as solitary or localized fibrous tumors of the pleura. ...
... Although the exact incidence of SFT is difficult to determine, SFTs constitute a small proportion (< 5%) of all pleural tumors [6]. SFTs may present at any age, but are most commonly seen between the ages of 50-70 years [2]. There does not seem to be a gender predilection with men and women being equally affected [7]. ...
... A pedicle can be radiologically visualized in 40% of cases [15]. Hence, due to the presence of a pedicle, significant tumor mobility, change in shape and location may be observed in sequential images [2,13]. Associated pleural effusion can also be seen in some instances [2]. ...
Solitary fibrous tumors (SFTs) are rare mesenchymal pleural neoplasms with an overall good prognosis and low recurrence rate if completely resected and if degree of differentiation is favorable. Within the last decade, advances in research have led to more reliable methods of differentiating SFTs from other soft tissue tumors. Historically, several markers were used to distinguish SFTs from similar tumors, but these markers had poor specificity. Recent evidence showed NAB2-STAT6 fusion gene to be a distinct feature of SFTs with 100% specificity and sensitivity. Surgical resection, with an emphasis on obtaining negative margins, is the mainstay of treatment for SFTs. Preoperative planning with detailed imaging is imperative to delineate the extent of disease and vascular supply. One important radiologic distinction to aid delineation of a pleural-based tumor compared to a pulmonary parenchymal-based tumor is the angle that the tumor forms with the chest wall, which is obtuse for a pleural-based tumor, and acute for tumors of the lung parenchyma. Often, preoperative tissue diagnosis is not available, and surgery is both diagnostic and curative. Intraoperatively, emphasis should be on complete resection with negative margins. SFTs are resected via several approaches: thoracotomy, sternotomy with the option of hemi-clamshell extension, video-assisted thoracoscopic surgery, and robotic approach, which is increasingly being used and is our preference. We recommend a minimally invasive approach for most lesions, and have resected SFTs of the pleura that are up to 12 cm with the robotic approach. However, the current literature often cites 5 cm as the cut off for an open thoracotomy. Nevertheless, even with larger tumors, a minimally invasive robotic approach is our preference and practice. For giant SFTs (> 20 cm), an open approach may be preferable. Multiple thoracotomies and rib resection may be required to gain adequate exposure and ensure complete resection in these tumors. However, it is noteworthy that most of these tumors have a soft consistency and thus, once bagged, can easily be removed minimally invasively, and thus minimally invasive approach should not be completely ruled out. Recurrence in SFTs usually results from incomplete resection and redo surgery may portend a favorable prognosis.
... Solitary fibrous tumors (SFTs) are rare, mesenchymal neoplasms originating from fibroblastic or myofibroblastic tissue [1]. Although once thought to be a class of mesotheliomas, SFTs are immunohistochemically distinct due to their presence of vimentin, CD34, and lack of cytoplasmic keratins [2][3][4]. SFTs are most commonly found in the thorax, but have also been identified in extrathoracic locations including the head, neck, breast, abdomen, pelvis, extremities, and scrotum [5,6]. SFT's of the pleura (SFTPs) are very rare, occurring at an incidence of 2.8 per 100,000 [7]. ...
... They have a distinct histological fingerprint allowing them to be disambiguated from other neoplasms such as mesothelioma or other lung sarcomas. Differentiation of SFTP includes tissue that is CD34-positive, vimentin-positive, and keratin-negative [2][3][4]. The majority of SFTP are benign, although when malignant, can paradoxically be CD34negative [12]. ...
Background
Solitary fibrous tumors of the pleura are rare diseases of the thoracic cavity. They frequently grow unnoticed until they exert compressive effects on adjacent organs. Treatment of solitary fibrous tumors of the pleura is surgical resection. Post-operative surveillance is recommended to identify early recurrent disease.
Case presentation
We present a rare case of a 76-year-old female patient with no previous pulmonary history who presented with progressive dyspnea, fatigue, and involuntary weight loss. On chest X-ray and computed chest tomography scan, she was found to have a 16.7 cm × 12.8 cm × 10.1 cm bulky mass occupying the left hemithorax with associated compressive atelectasis of the lung. She underwent a computed tomography guided biopsy that revealed the mass to be a solitary fibrous tumor. The patient underwent left muscle sparing lateral thoracotomy with complete resection of the tumor. Post procedure, the left lung fully expanded. 18 months post-resection, she developed a 3.3 cm × 1.7 cm tumor along the left internal thoracic artery lymph node chain which was histologically identical to the resected tumor. The patient is currently being treated with bevacizumab and temozolomide.
Conclusion
Solitary fibrous tumors are very rare pleural tumors. Surgical resection is the treatment of choice followed by close post-operative surveillance.
... To distinguish these usually benign tumors from the more common malignant mesothelioma, Clagett et al. in 1952 coined the term localized fibrous mesothelioma 5,6 . Nowadays the tumor is commonly known as localized or solitary fibrous tumor of the pleura (SFTP) 1 and there is broad agreement about their nonmesothelial origin based on immunohistochemical and ultrastructural findings [7][8][9][10] . Immunohistochemistry and electron microscopy have clarified that these tumors originate from the submesothelial, noncommited mesenchymal layer, a pluripotent tissue with differentiation potential to bone, cartilage or blood vessels 9,10 . ...
... Nowadays the tumor is commonly known as localized or solitary fibrous tumor of the pleura (SFTP) 1 and there is broad agreement about their nonmesothelial origin based on immunohistochemical and ultrastructural findings [7][8][9][10] . Immunohistochemistry and electron microscopy have clarified that these tumors originate from the submesothelial, noncommited mesenchymal layer, a pluripotent tissue with differentiation potential to bone, cartilage or blood vessels 9,10 . SFTPs are usually detected as asymptomatic lesions on routine chest radiograph in adult patients. ...
Background
Solitary fibrous tumors of the pleura are rare and slow-growing neoplasms originating from the mesenchymal tissue underlying the mesothelial layer of the pleura. These tumors may have an unpredictable clinical course. Most cases occur in the sixth or seventh decades of life with no gender predilection, and more than 80% of cases are benign. The predominant clinical symptoms and signs are dyspnea, cough, chest pain, finger clubbing and hypoglycemia. However, because many patients are asymptomatic, the incidence rates are affected by the likelihood of its incidental detection, often through medical imaging of the chest. Surgical resection is the treatment of choice and is usually curative, even though local recurrence can occur many years after an adequate resection.
Methods
We reviewed the literature by performing a computerized search of MEDLINE, CANCERLIT and Embase with the terms fibrous tumor, pleura, surgery, immunohistochemical analysis. Articles and abstracts were also identified by back-referencing from other relevant papers.
Results
The clinical, radiological and pathological features of a 48-year-old woman with a primary solitary fibrous tumor of the pleura are reviewed and a literature search for other reported cases has been performed.
Conclusions
Although localized fibrous tumors of the pleura are considered histologically benign, there is a risk of recurrence and malignant transformation. Complete surgical resection is mandatory and long-term clinical and radiological follow-up is indicated in all patients. For malignant cases complete surgical resection may not be adequate and studies are needed to define the role of preoperative and postoperative systemic treatment. Diagnosis is very difficult in limited samples such as fine-needle aspiration or needle-core tissue biopsy, and immunohistochemical analysis may be useful to differentiate solitary fibrous tumor of the pleura from mesothelioma and other similar tumors.
... To distinguish these usually benign tumors from the more common malignant mesothelioma, Clagett et al. in 1952 coined the term localized fibrous mesothelioma 5,6 . Nowadays the tumor is commonly known as localized or solitary fibrous tumor of the pleura (SFTP) 1 and there is broad agreement about their nonmesothelial origin based on immunohistochemical and ultrastructural findings [7][8][9][10] . Immunohistochemistry and electron microscopy have clarified that these tumors originate from the submesothelial, noncommited mesenchymal layer, a pluripotent tissue with differentiation potential to bone, cartilage or blood vessels 9,10 . ...
... Nowadays the tumor is commonly known as localized or solitary fibrous tumor of the pleura (SFTP) 1 and there is broad agreement about their nonmesothelial origin based on immunohistochemical and ultrastructural findings [7][8][9][10] . Immunohistochemistry and electron microscopy have clarified that these tumors originate from the submesothelial, noncommited mesenchymal layer, a pluripotent tissue with differentiation potential to bone, cartilage or blood vessels 9,10 . SFTPs are usually detected as asymptomatic lesions on routine chest radiograph in adult patients. ...
Background:
Solitary fibrous tumors of the pleura are rare and slow-growing neoplasms originating from the mesenchymal tissue underlying the mesothelial layer of the pleura. These tumors may have an unpredictable clinical course. Most cases occur in the sixth or seventh decades of life with no gender predilection, and more than 80% of cases are benign. The predominant clinical symptoms and signs are dyspnea, cough, chest pain, finger clubbing and hypoglycemia. However, because many patients are asymptomatic, the incidence rates are affected by the likelihood of its incidental detection, often through medical imaging of the chest. Surgical resection is the treatment of choice and is usually curative, even though local recurrence can occur many years after an adequate resection.
Methods:
We reviewed the literature by performing a computerized search of MEDLINE, CANCERLIT and Embase with the terms fibrous tumor, pleura, surgery, immunohistochemical analysis. Articles and s were also identified by back-referencing from other relevant papers.
Results:
The clinical, radiological and pathological features of a 48-year-old woman with a primary solitary fibrous tumor of the pleura are reviewed and a literature search for other reported cases has been performed.
Conclusions:
Although localized fibrous tumors of the pleura are considered histologically benign, there is a risk of recurrence and malignant transformation. Complete surgical resection is mandatory and long-term clinical and radiological follow-up is indicated in all patients. For malignant cases complete surgical resection may not be adequate and studies are needed to define the role of preoperative and postoperative systemic treatment. Diagnosis is very difficult in limited samples such as fine-needle aspiration or needle-core tissue biopsy, and immunohistochemical analysis may be useful to differentiate solitary fibrous tumor of the pleura from mesothelioma and other similar tumors.
... 1 3 SFTs arise most commonly in the 5th-7th decades of life but can occur at any age. 4 There is no known association between SFTs and any environmental exposures, and there are no known inherited predisposing risk factors. 5 SFTs arising from the prostate are extremely rare, with only around 40 cases reported in the literature to date. 1 They exist on a spectrum of prostatic spindle cell neoplasms, altogether representing less than 1% of all prostate tumours. ...
Solitary fibrous tumours (SFTs) are rare mesenchymal neoplasms composed of spindle cells, most often occurring in the pleura. SFTs arising from the prostate are exceptionally rare, with only around 40 cases reported in literature to date. We report a man in his 60s who was referred to our clinic for elevated prostate-specific antigen and presented with mild obstructive lower urinary tract and defecatory symptoms. Prostate needle-core biopsy revealed neoplastic spindle cells that strongly expressed CD34. Cross-sectional imaging demonstrated a 12 cm locally advanced heterogeneous prostate mass with intravesical extension and mass effect on the anterior rectum. Radical cystoprostatectomy with orthotopic neobladder reconstruction was performed, and the diagnosis of primary prostatic SFT was made based on histological characteristics and immunophenotyping. We present diagnostic, clinical management and prognostic considerations in patients with primary prostatic SFT.
... immunohistochemically distinct due to their presence of vimentin, CD34, and lack of 39 cytoplasmic keratins [2][3][4]. SFTs are most commonly found in the thorax, but have also been 40 identified in extrathoracic locations including the head, neck, breast, abdomen, pelvis, 41 extremities, and scrotum [5, 6]. SFT's of the pleura (SFTPs) are very rare, occurring at an 42 incidence of 2.8 per 100,000 [7]. ...
Background: Solitary fibrous tumors of the pleura are rare diseases of the thoracic cavity. They frequently grow unnoticed until they exert compressive effects on adjacent organs. Treatment of solitary fibrous tumors of the pleura is surgical resection. Post-operative surveillance is recommended to identify early recurrent disease.
Case Presentation: We present a rare case of a 76-year-old female patient with no previous pulmonary history who presented with progressive dyspnea, fatigue, and involuntary weight loss. On chest X-ray and computed chest tomography scan, she was found to have a 16.7 cm x 12.8 cm x 10.1 cm bulky mass occupying the left hemithorax with associated compressive atelectasis of the lung. She underwent a computed tomography guided biopsy that revealed the mass to be a solitary fibrous tumor. The patient underwent left muscle sparing lateral thoracotomy with complete resection of the tumor. Post procedure, the left lung fully expanded. 18 months post-resection, she developed a 3.3 cm x 1.7 cm tumor along the left internal thoracic artery lymph node chain which was histologically identical to the resected tumor. The patient is currently being treated with bevacizumab and temozolomide.
Conclusion: Solitary fibrous tumors are very rare pleural tumors. Surgical resection is the treatment of choice followed by close post-operative surveillance.
... Although Wagner was the first to report a case of a primary localized pleural tumour in 1871 , the first description of the SFTP (9) features is attributed to Klemperer and Rabin and due to the fact that they were (10) originally thought to arise from the mesothelium of the pleura they were classified as localized mesotheliomas. (11) have led to great confusion regarding the underneath the pleural mesothelium , the (12,13) mesenchymal origin being supported by the lack of cytoplasmic keratin expression and the positive staining for vimentin and CD34 . (14,15) These findings led to the change of nomenclature from localized mesothelioma to SFTP . ...
Solitary fibrous tumours of the pleura (SFTPs) are rare neoplasms, usually described as relatively benign neoplasms and only 10-20% presenting malignant features. Imagistic investigations are useful in the incipient evaluation of SFTPs, and the histopathological and immunohistochemical examinations after surgical resection are mandatory for establishing the diagnosis and for differentiating SFTPs from other aetiologies of pleural masses. The unpredictable evolution (10%-20% of the cases reported in literature display malignant features) and limited data regarding the treatment needs an early detection, a complete surgical resection and long-term imagistic follow-up. We present a case of SFTPs alongside a review of the typical clinical, imagistic and pathologic features consistent with this diagnosis.
... SFT of pleura constitutes less than 5% of pleural tumours, 80% arise from the visceral pleura and the remainder from parietal pleura. 2 SFT also affects other sites such as peritoneum, pericardium and in nonserosal sites such as lung parenchyma, upper respiratory tract, orbit, thyroid, parotid gland, or thymus. The origin of these tumours is controversial, and their nomenclature not consistent, with names such as fibroma, fibrosarcoma, localized fibrous mesothelioma, submesothelial fibroma, benign fibrous mesothelioma, etc. 3 Generally, there is no apparent genetic predisposition for the tumour and no relationship to exposure to asbestos, tobacco, or any other environmental agent. ...
Most pleural neoplasms are metastatic in origin. Primary tumours of the pleura are rare and categorized as diffuse or localized. Diffuse or malignant mesothelioma is more common, related to asbestos exposure, and associated with a poor prognosis. Localized or solitary fibrous tumour (SFT), of the pleura is a less common neoplasm of controversial histogenesis and is unrelated to asbestos exposure. Surgical resection of benign solitary fibrous tumours is usually curative. We report a rare case of Giant solitary fibrous tumour of pleura with related literature.
... Tumor cells were initially thought to be of mesothelial-cell origin since first report of pleural SFTs was described as localized fibrous mesotheliomas in 1931 [1]. But a series of studies has indicated the fibroblastic or myofibroblastic phenotype of the tumor cells [2][3][4]. It is now known that SFT can develop in a variety of extrapleural tissues. ...
We report a case of pancreatic hamartoma-like solitary fibrous tumor which was differentiated from pancreatic hamartoma with the detection of NAB2-STAT6 fusion, a specific mutation for solitary fibrous tumors. A pancreatic well-demarcated solid nodule,
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mm, of 82-year-old man was surgically enucleated. Microscopic findings were close to a pancreatic hamartoma that consisted of sparsely distributed pancreatic ducts and acini in heavily collagenized fibrous stroma. Neither islet nor peripheral nerve existed in the tumor. The fibroblastic cells in the stroma were immune-positive for CD34, CD99, and bcl-2. But these expressions were not decisive in the differentiation between solitary fibrous tumor and pancreatic hamartoma, because CD34 was positive for both tumors, and CD99 and bcl-2 expressions were not elucidated in the previous cases of pancreatic hamartomas. Thus, we evaluated NAB2-STAT6 fusion. The fibroblastic cells were positive for STAT6 and sequencing analysis revealed the gene fusion between NAB2 exon 4 and STAT6 exon 2, with which the final diagnos is of solitary fibrous tumor was achieved. In conclusion, detection of NAB2-STAT6 fusion has a great diagnostic value for pancreatic solitary fibrous tumors with hamartoma-like features.
... They are also known as benign localized mesothelioma, submesothelioma, or subserosal fibroma. 1,2) In 1931, Klemperer and Rabin3 divided primary tumors of the pleura into two categories: diffuse mesothelioma and localized mesothelioma. 3) In 1942, Stout and Murray, 4) on the basis of in vitro cell culture findings, proposed mesothelial cells as the source of the so-called localized mesothelioma which was confirmed by other studies with the help of immunohistochemical staining. ...
A 43-year-old woman presented to us with progressive breathlessness, dry cough and weight loss. A chest radiograph showed homogeneous opacification of the entire left hemithorax. A contrast enhanced computed tomography (CECT) scan of the thorax showed a large intrathoracic mass occupying almost the entire left hemithorax and appeared grossly inoperable. A transcutaneous CT guided tru-cut biopsy revealed a solitary fibrous tumour. We reviewed the CT scans based on the biopsy report, and, in retrospect, the mediastinal vessels seemed more stretched and pushed by the tumor rather than directly infiltrated by it. We performed an exploratory thoracotomy and to our surprise, were able to dissect the mass quite easily off the mediastinum. She had an uneventful postoperative recovery, and the final histopathology confirmed a solitary fibrous tumor. We report this case to emphasize that a cursory clinico-radiological interpretation can dissuade surgical intervention in these patients.
... Because its pathologic characteristics was first described by Klemperer and Rabin 1 in 1931, the nomenclature has become confused, and the disease has also been referred to as a localized mesothelioma, localized fibrous tumor, fibrous mesothelioma, or a pleural fibroma. 2 The further development of electron microscopy and immunohistochemistry has clarified that the tumor does not originate from the mesothelial layer but from the submesothelial, noncommitted mesenchymal layer. 3,4 Thus, the various names used for this disease have become unified, and the disease is now referred to as solitary or localized fibrous tumors of the pleura. Mesenchyme is pluripotent tissue and possesses diverse differentiation potential to bone, cartilage, or blood vessels. ...
To present our experience of video-assisted thoracoscopic surgery (VATS) for patients with solitary fibrous tumors of the pleura (SFTPs) and to discuss the treatment of choice of such neoplasms.
Between June 2000 and September 2008, 21 patients with SFTPs (9 men and 12 women) underwent VATS at our department. The mean age was 52.5 years (range, 33-76 years).
Surgical excision was performed in all patients. Surgical excision was performed by VATS in 15 patients (71.4%), by VATS plus a small thoracotomy (<5 cm) in 4 patients (19.0%), and by posterolateral thoracotomy accompanied by VATS in 2 patients (9.5%). Mean chest drain duration was 2.3 days (range, 1-4 days), and the mean hospital stay was 7.2 days (range, 4-15 days). There were 18 pathologically benign SFTP cases (85.7%) and 3 malignant SFTP cases (14.3%). There was no operative morbidity or mortality. No recurrence or metastasis of SFTPs developed during postoperative median follow-up period of 43 months.
Complete resection and close follow-up for years after operation is recommended for SFTPs. VATS may play an important role in reducing the size of the thoracotomy incision in the treatment of SFTPs, which results in less invasive surgery.
... O principal fator prognóstico para boa evolução parece ser o grau de ressecabilidade da lesão 28 . Embora pareça existir também correlação entre índice mitótico e atipia celular, isso não se confirmou em uma série de casos, visto que apresentaram aspectos histológicos desfavoráveis, porém evoluíram de maneira benigna 15,30,31 . ...
O tumor fibroso solitário (TFS) é neoplasia mesenquimal rara, originalmente descrita na pleura e sendo mais recentemente também observada em vários outros sítios. Sua extensão para estruturas adjacentes não é incomum. O acometimento da meninge pelo TFS é raro, havendo relato de apenas vinte e seis casos na literatura. Apresentamos o caso de uma paciente de 25 anos, sexo feminino, com crises convulsivas tônico-clônicas generalizadas desde há seis anos. Durante a investigação, foi diagnosticado tumor em região occipital esquerda. A paciente foi submetida à craniotomia occipital, com exérese completa do tumor. O diagnóstico histopatológico e imuno-histoquímico foi de tumor fibroso solitário da meninge. Após seguimento pós-operatório por três anos, a paciente mantém o exame neurológico sem alterações e não apresenta evidência de recidiva nos controles tomográficos. É apresentada também uma breve revisão da literatura.
Context.—Overwhelmingly, the most common neoplasm involving the pleura is metastatic carcinoma. In contrast, diffuse malignant mesothelioma occurs relatively rarely; however, it is nonetheless the most common neoplasm primary to the pleura. Metastatic carcinoma and diffuse malignant mesothelioma each have their own prognostic and therapeutic characteristics. Other primary pleural neoplasms occur uncommonly or rarely, with their own prognostic and therapeutic characteristics.
Objective.—To review primary pleural neoplasms other than diffuse malignant mesothelioma, to better ensure correct diagnosis and optimal assessment of prognosis and treatment.
Data Sources.—Literature review and primary material from the authors' institutions.
Conclusions.—A nonexhaustive group of uncommon to rare benign and malignant primary pleural neoplasms— other than diffuse malignant mesothelioma—are presented, of which one must be aware in order to maintain an appropriate index of suspicion to include them in the differential diagnosis of a pleural tumor.
Primary tumors of the pleura are relatively rare both in children and adults. Metastatic disease to the pleura is the most common neoplastic process involving the pleural surfaces and far outnumbers primary benign and malignant pleural neoplasms. Malignant mesothelioma represents the most common primary malignant neoplasm of this site, with an estimated 2000 newly diagnosed cases in the United States each year [Cagle and Allen, Respirology 16:430–438, 2011; English and Leslie, Clin Chest Med 27:157–180, 2006; Ai and Stevenson, Oncologist 19:975–984, 2014]. Aside from malignant mesothelioma, there is a variety of more uncommon primary pleural neoplasms, both benign and malignant, that need to be considered in the differential diagnosis. Since many of these entities can demonstrate similar clinical, imaging, and macroscopic features, awareness of these conditions as well as accurate histopathologic diagnosis is extremely important as the treatment and prognosis for these diverse tumors can vary greatly. Novel immunohistochemical and molecular markers allow for a confirmatory diagnosis in some of the entities; however, careful morphologic assessment and evaluation of the clinical context are indispensable for the correct diagnosis, not only to distinguish between different primary pleural neoplasms but also to exclude metastatic disease. This chapter provides an overview of the most common primary pleural neoplasms other than malignant mesothelioma and reviews their typical clinical presentation as well as morphologic, immunophenotypic, and molecular characteristics.
Primary mesenchymal tumors of the lung are uncommon tumors that often resemble their counterparts in the soft tissue. Both benign and malignant tumors of mesenchymal origin may arise from the bronchopulmonary system. These may be of single lineage differentiation and show fibroblastic, muscle, cartilage and bone, adipose, myxoid, neurogenic, or neuroectodermal features or be composed of heterogenous cell types like hamartomas or malignant triton tumor. The incidence for these tumors is very low and based on the current literature it appears that primary pulmonary sarcomas account for less than 1 % of all primary lung tumors.
Der Thymus ist ein branchiogenes, paarig angelegtes Organ, das sich beim Menschen aus den ventralen Abschnitten vorwiegend der III. Schlundtasche (Thymus III), möglicherweise aber auch aus der IV. Schlundtasche (Thymus IV), entwickelt. Insofern besäße der Thymus, entwicklungsgeschichthch gesehen, eine metamerale („branchiomere”) Struktur (Hammar 1905, 1909, 1911a und 1911b, Sobotta 1914, Bargmann 1943, Tesseraux 1959). Allerdings dürfte beim Menschen ein der IV. Schlundtasche entstammender Thymus nur selten (evtl. akzessorisches Thymusgewebe) und wahrscheinlich nur vorübergehend entwickelt sein (Groschuff 1900, Jedlicka 1928, Politzer U. Hann 1935).
Aus Gründen der Tumortopographie (vorderes Mediastinum) spielen in der Differentialdiagnose primärer Thymustumoren neben malignen Lymphomen vor allem Keimzelltumoren (Teratome), Metastasen und tumorähnliche Läsionen eine Rolle (Tabelle 51). Die im Einzelfall problematische topographische Zuordnung maligner Lymphome zu thymogenen und/oder mediastinalen Lymphomen wurde bereits auf S. 230 diskutiert. Metastasen können sich aus praktisch allen Organregionen im Mediastinum entwickeln. Im folgenden soll lediglich auf die Keimzelltumoren/Teratome, auf die solitären fibrösen Pleuratumoren, auf die angiofollikuläre Lymphknotenhyperplasie und auf die fibrosierende Mediastinitis eingegangen werden.
Introduction: Solitary fibrous tumors of pleura (SFTP) are occasionally associated with paraneoplastic syndromes such as hypoglycemia and diffuse skeletal hyperostosis. Clinical case: We report a 60 years old male presenting with episodes of disorientation and inappropriate behavior, along with cough and weight loss. On physical examination there was digital clubbing. A chest X ray showed a big tumor in the right hemithorax. Fasting blood glucose was 24 mg/dl and erythrocyte sedimentation rate was elevated. Large bone X rays showed hyperostosis. A needle biopsy of the tumor showed a SFTP. The tumor was excised and the final pathological diagnosis was a benign SFTP. Hypoglycemia subsided after surgery. After four months of follow up, finger clubbing was disappearing.
Introduction
The pleura is host to many diseases, some systemic, others spreading from the underlying lung. Lung carcinoma metastases are the commonest lesions seen by pathologists. The most frequent cause of pleural problems is an effusion, secondary to congestive cardiac failure. This chapter will consider normal pleural physiology, as well as benign and malignant processes.
The pleural space, separating the lung and chest wall, contains a small amount of liquid that lubricates the pleural surfaces during breathing (see Chapter 1). The volume of fluid in the pleural space is small, in the range of 0.2–0.5 ml. Normally, the protein and cellular content is low, with no inflammatory cells. The thin layer of liquid between the pleural surfaces has the important function of providing mechanical coupling between the chest wall and lung. For this connection to be effective, the volume of pleural liquid required for lubrication must be kept to a minimum. In addition, the colloid osmotic pressure must be low to keep this volume small. This fluid ensures instantaneous transmission of perpendicular forces between the two structures, and allows their sliding movement in response to shearing forces.
Introduction: Solitary fibrous tumor is a rare mesenchymal tumor affecting mainly the pleura, the visceral pleura is the most commonly affected. It is usually a benign tumor but may have an unpredictable behavior and a malignant potential, complete excision is the standard of treatment. We present a case of solitary fibrous tumor of the mediastinal pleura which is a very rare incidence. Also, we reviewed the literature related to the condition. © 2011 DAR Publishers/University of Jordan. All Rights Reserved.
Coirespondencia: Servicio de Cirugía Torácica. Hospital General Universitario Gregorio Marañón. Doctor Esquerdo. 46. 28007 Madrid.
This article has no abstract; the first 100 words appear below.
Presentation of Case A 29-year-old woman was admitted to the hospital because of a left thoracoabdominal mass. She was well until 18 months earlier, when she began to experience discomfort in the left flank during her first pregnancy. Three months later her son was delivered. The child was breast-fed for the first five months, and then bottle feedings were substituted. Lactation persisted, with amenorrhea. The discomfort in the left flank progressed to local pain and tenderness and was accompanied by a marked decrease in libido. Six months before entry an obstetrician administered a single dose of medroxyprogesterone acetate, which was . . .
Introduction: Solitary fibrous tumors of pleura (SFTP) are occasionally associated with paraneoplastic syndromes such as hypoglycemia and diffuse skeletal hyperostosis. Clinical case: We report a 60 years old male presenting with episodes of disorientation and inappropriate behavior, along with cough and weight loss. On physical examination there was digital clubbing. A chest X ray showed a big tumor in the right hemithorax. Fasting blood glucose was 24 mg/dl and erythrocyte sedimentation rate was elevated. Large bone X rays showed hyperostosis. A needle biopsy of the tumor showed a SFTP. The tumor was excised and the final pathological diagnosis was a benign SFTP. Hypoglycemia subsided after surgery. After four months of follow up, finger clubbing was disappearing.
Four autopsy cases of mesothelioma were studied histologically and electron microscopically. One of them showed a pure epithelial type of the peritoneal origin, characterised by a tremendous production of hyaluronic acid. The other three tumors originated from the pleura revealed a histology of biphasic type mesothelioma, which showed an admixed tubular and fibrous pattern and consisted of small-sized cells with slight atypia. However, in some places of these tumors they showed considerable atypical features appearing like an anaplastic or squamoid carcinoma and/or spindle cell sarcoma. Hyaluronic acid was histologically demonstrated in the cytoplasmic vacuoles as well as in the luminal space surrounded by the tumor cells. Electron microscopically, varied numbers of microvilli and desmosome-like attachments were found on the surface of the tumor cells. Mitochondria were small and round. Well-developed rERs tended to encircle mitochondria and to dilate forming cisternae. Various amounts of microfilaments were found in the cytoplasm. The tumor cells which were rich in the latter two components, dilated rERs and microfilaments, resembled fibroblasts. Some tumor cells had phagosomes including dense and fine granules similar to ferritin, suggesting their phagocytotic activity. The hyaline matrix, common to the biphasic type tumor which was largely composed of dense collagenous tissues, was demonstrated to contain hyaluronic acid by histochemistry, and it was suggested that some secretory substances of the tumor cell may participate in composing the hyaline matrix to some extent. ACTA PATHOL. JPN. 34: 1411–1424, 1984.
A solitary fibrous tumor of the pleura (SFTP) in a 37-year-old woman was reported as a rare pleural tumor based on morphological, immunohistochemical, and electron microscopic studies. The results showed that the tumor was composed of spindle-shaped cells forming fascicular and interlacing patterns with a mixture of mature collagen. The tumor cells coexpressed vimentin and CD34 and lacked cytokeratin reactivity. Ultrastructurally, there were abundant collagenous fibrillae surrounding spindle-shaped cells in which the junctional complex, basement membrane-like structure, and microvilli were not seen. From literature review and observation of the morphological features around the tumor, we consider that the tumor originated from the stromal cells subjacent to the mesothelium.
Background. Solitary fibrous tumor is a rare mesenchymal neoplasm. We report a rare case of multiple metastases 11 years after resection of the initial tumor. Case. A 75-year-old woman was admitted to our hospital with swelling of the right parotid gland. Computed tomographic scanning revealed a tumor, 20 mm in diameter, in the right parotid gland. In spite of negative aspiration cytology, the tumor had enlarged in the previous year and was resected. Simultaneously, radiographic examination of the chest revealed three pulmonary nodules. Under the suspicion of metastatic tumor, we resected all of these tumors. These tumors showed hypercellularity of spindle cells with markedly atypical nuclei, immunoreactive with CD34 and bcl-2. Histopathologically, a diagnosis of solitary fibrous tumor was made. These tumors showed the same histological features as the tumors resected from the retroperitoneal space 11 years previously. Conclusion. From the histopathologic features and the clinical course, we concluded that the solitary fibrous tumor in the retroperitoneal space had metastasized to the lung and parotid gland. Long-term follow-up is recommended for solitary fibrous tumors, because of its potential malignancy.
We experienced a case of 58-year-old female with solitary fibrous tumor of the pleura, which had been resected by the video- assisted thoracoscopic surgery for definitive diagnosis. Solitary fibrous tumors of the pleura are rare and have confusing pathological characteristics, which have been elucidated by the advancement of the immuno-histochemical analyses. We report the case of this ailment with reference to other relevant literature. (Tanaffos 2005; 4(15): 57-59)
Pleural fibroma, or fibrous tumor of the pleura, is an uncommon entity which is characterized by slow proliferation of undifferentiated, intermediary or mature fibroblasts associated with collagen fibers forming a tumor stroma.
We report a case in a 49-year-old man who developed exercise-induced dyspnea and right chest pain. The thoracic CT scan revealed the presence of a mass in the right lung base composed of heterogeneous encapsulated tissue. Tumor resection was performed leading to the histological diagnosis of pleural fibroma. Immunohistochemistry tests revealed positive vimetin and CD34, and negative cytokeratin uptake. These immunohistochemistry data contributed to the differential diagnosis with malignant pleural mesothelium.
Pleural fibroma is a benign tumor in 80% of the cases. Prognosis is excellent. Local recurrence is exceptional and generally occurs after incomplete resection. Radial surgical treatment determines the prognosis and is required to prevent local recurrence. Other criteria of malignancy are not correlated with the clinical course of this type of tumor.
Zusammenfassung. Der lokalisierte fibrse Tumor der Pleura ist ein seltener, langsam wachsender, benigner Tumor, der seinen Ursprung von den
submesothelialen Stammzellen der Pleura visceralis nimmt. Klinisch findet sich in vielen Fllen ein asymptomatischer Verlauf,
wobei jedoch bei wenigen Fllen Tumor-assoziierte Hypoglykmien bis hin zum hypoglykmischen Koma beobachtet werden. Bei diesen
Nicht-Inselzell-Tumoren findet man laborchemisch eine Erhhung des paraneoplastisch gebildeten IGF-II im Serum, der eine 2–3
fach hhere Wirkpotenz als das physiologische Insulin aufweist. Darber hinaus kommt es zu einer reduzierten Synthese von
IGFBP-3 (insulin-like growth factor binding protein), das durch Komplexbildung die endokrine Wirkung des IGF-II hemmt. Die
Therapie der Wahl ist die chirurgische Tumorresektion. In dem hier geschilderten Fall fanden sich bei einem 72 jhrigen Mann
klinisch trotz eines bekannten Diabetes mellitus Typ II ausgeprgte Hypoglykmien. Bei der diagnostischen Abklrung fand sich
ein von der Pleura visceralis im rechten Hemithorax ausgehender Tumor. Nach der chirurgischen Resektion des Tumors waren diese
Hypoglykmien nicht mehr nachweisbar.
Solitary fibrous tumor of the pleura (SFTP) is a rare tumor of mesenchymal origin which can grow to a large size and present with symptoms of cough and pleuritic chest pain. No specific etiological factors for SFTPs are known and they may grow undetected for several years. These tumors are usually benign and may mimic a variety of malignancies. SFTPs are often detected as peripheral opacities on chest X-ray. Unfortunately, fine needle aspiration rarely provides adequate information for a definitive diagnosis. Imaging with computed tomography provides details about the size and extent of any invasion into adjacent tissues. Surgical resection is the mainstay of treatment, and immunohistochemistry of the resected tumor often provides confirmation of the diagnosis. Some SFTPs have been observed to be malignant, and surgical intervention is often lifesaving. There is no adequate data to support the usage of radiotherapy and chemotherapy in the treatment of SFTPs. This tumor exemplifies malignancies which require surgical resection to preempt worse outcomes. Awareness of their presentation and clinical course may help the clinician provide a prompt referral to the thoracic surgeon for resection.
Solitary fibrous tumor (SFT) is a ubiquitous neoplasm that arises most commonly from the pleura. SFT arising within lung parenchyma (intrapulmonary SFT) has been rarely reported and is therefore not well recognized. We present a clinicopathologic and immunohistochemical study of 24 cases of primary intrapulmonary SFT. Patients' ages ranged from 44 to 83 years (mean, 58 y). None of the patients had evidence or history of a similar tumor elsewhere. Tumor size ranged from 2.3 to 22 cm (mean, 8.5 cm). On the basis of the degree of cytologic atypia, cellularity, mitotic activity, and areas of necrosis, the lesions were divided into low-grade, intermediate-grade, and high-grade histology. Twenty-one tumors showed the conventional features of SFT of low-grade histology (<5 mitoses per 10 high-power fields), with alternating bands of rope-like collagen flanked by a bland-appearing spindle cell proliferation. Hemangiopericytic, angiofibromatous, and a neural-like plexiform growth pattern were also observed. Five of 21 cases showed an "adenofibromatous" appearance imparted by entrapped normal airspaces at the advancing edges of the lesion. One intermediate-grade tumor showed overall increased cellularity with plump, pleomorphic nuclei, 5 to 10 mitoses per 10 high-power fields, and focal areas of classic SFT. Two cases showed high-grade features at initial presentation, with areas resembling a pleomorphic high-grade sarcoma admixed with foci of conventional, low-grade SFT. Immunohistochemical staining analyses performed in 13 cases showed positivity of the tumor cells for CD34, bcl-2, and CD99 in the majority of cases tested. Clinical follow-up was available in 18 patients, with long-term follow-up (>5 y) in 6. Fourteen (14/18) patients were alive and well without evidence of disease 1 month to 14 years after initial diagnosis. Three patients died of their tumors after 4, 5, and 7 years; in 2 of them the initial tumor was of low-grade histology, but the recurrence/metastases showed a high-grade histology; the third fatal case showed a tumor with high-grade histology at initial diagnosis. One patient with intermediate-grade histology also had chest wall metastases at 5 years but was subsequently lost to follow-up. The results of our study indicate that although tumors with overtly malignant histologic features can be expected to behave as high-grade sarcomas, tumors with bland-appearing morphologic features at presentation may also follow an aggressive behavior. Adequate excision with close clinical follow-up, thus, appears to be the most prudent course of action for the management of primary intrapulmonary fibrous tumors.
Introduction:
Available data on the malignant solitary fibrous tumor of the pleura (mSFTP), a very rare neoplasm with unpredictable prognosis, are scarce. The aim of this study is to collectively analyze the aggregated data from the largest series in the English literature to date, a multicenter, 10-year study of 50-cases.
Methods:
We retrospectively reviewed the clinical records of patients who underwent surgical resection for mSFTP in the period between January 2000 to July 2010. Long-term survival (LTS) and 5-year disease-free survival were analyzed in detail.
Results:
There were 24 men and 26 women (median age, 66 years; age range, 44-83 years). Thirty-two patients (64%) were symptomatic. A malignant pleural effusion was diagnosed in 12 cases. Surgical resection included isolated mass excision in 13 patients and extended resection in 35. In the remaining two cases only biopsies were undertaken. The resection was complete in 46 cases (92%). Adjuvant treatment was administered to 15 patients. Median follow-up was 116 months (range, 18-311 months). Overall LTS and disease-free survival were 81.1% and 72.1%, respectively. Fifteen patients (30%) experienced a relapse of the disease. Complete resection yielded much better LTS than partial resection (87.1% versus 0%; p < 0.001). At the Cox regression analysis, incomplete resection (hazards ratio [HR]: 39.02; 95% confidence interval [CI]:4.04-380.36; p = 0.002) and malignant pleural effusion (HR: 3.44; 95%CI: 0.98-12.05; p = 0.053) were demonstrated to be risk factors for earlier death. At multivariate analysis, chest-wall invasion and malignant pleural effusion increased the risk of recurrence (HR: 4.34; 95%CI: 1.5%-12.6%; p = 0.007 and HR: 3.48; 95%CI: 1.1%-11.0%; p = 0.038, respectively).
Conclusions:
Surgical resection remains the treatment of choice for mSFTP. Relapse is common (approximately 30%). Incomplete resection and malignant pleural effusion at diagnosis impact LTS negatively.
Two cases of fibrous mesothelioma are presented. The first is a malignant tumor containing bundles of spindle-shaped cells with a dense reticulin network and nests of epithelial-like cells. The second is a benign tumor made up of spindle-shaped cells arranged in bundles with abundant reticulin and collagen fibers. Tissue culture in the first case revealed plaques similar to those formed by epithelial tumors. The second case had a fibroblastic pattern with single isolated spindle-shaped cells. These findings confirmed the mesothelial nature of fibrosarcomatous mesothelioma and supported the view that the so-called localized fibrous mesotheliomas could be fibroblastic neoplasms derived from the submesothelial connective tissue.
It is uncertain whether localized lesions of serosal membranes have a kinship to mesotheliomas or are truly fibromatous in nature. Ultrastructural and immunohistochemical investigations were carried out on 12 localized benign and malignant pleural and peritoneal tumours from 10 patients. Electron microscopic findings, including the consistent and non-fibroblastic cellular organization of localized neoplasms, the presence of some form of intercellular junctions in 7 of 10 cases, basal lamina deposition in 3 cases, and polarized microvilli in one case indicated a form of mesothelial differentiation. Using monoclonal and polyclonal antibodies, positive immunostaining of tumour cells for cytokeratin peptides was detected in one case, while antibody to vimentin stained four cases. Light microscopic, ultrastructural and immunohistochemical features of one benign localized serosal tumour, with a unique blend of epithelial and spindle cells, provided further evidence for a histogenic link between localized serosal tumours and diffuse epithelial mesotheliomas. On the basis of the current findings and reports in the literature, it would appear that the majority of localized tumours of serosal membranes are a subset of mesothelioma, while a minority are fibromas.
Two cases of primary intrapulmonary spindle-celled sarcomas unrelated to the pleura have been studied by electron microscopy, tissue culture and histochemistry. Ultrastructurally both tumors showed some desmosomial unions. The first case showed cytoplasmic filaments, nuclear inclusions, prominent rough endoplasmic reticulum and abundant collagen in the interstitium. The second tumor showed scanty organelles and a paucity of interstitial connective tissue fibers. In spite of their spindle morphology both tumors showed a similar pattern in vitro, growing as an epithelial plaque in the same way as previously described mesotheliomas and related tumors, such as synovial sarcomas. Histochemistry of the tumor mass allowed the identification of most of the cavities which were engulfed alveoli and bronchioli.
Both neoplasm were classified as intrapulmonary mesotheliomas. Their relationship to other pulmonary lesions is discussed.
In a series of eighteen diffuse malignant mesotheliomas, five cases were encountered in which thoracic surgery with benign nontumorous diagnosis preceded the development of a malignant mesothelioma by several years. The morphological findings in three of these five cases are compared with the morphology of the tumor specimens and an attempt is made to recognize the earliest possible malignant features. Crowding of mesothelial cells, their variability in size and nuclear hyperchromatism are pointed out as warning signs.
In relation to these findings, the histogenetic significance of predominantly fibroproliferative versus epithelial-like pleural lesions is discussed. A histogenetic classification, based on the studies of eighteen diffuse malignant mesotheliomas, two benign fibrous mesotheliomas, one pleural fibrosarcoma, and numerous pleural plaques as well as reactive mesothelial lesions, is offered. The therapeutic aspects are mentioned.
Five localized fibrous tumours of the pleura (benign mesothelioma) were studied ultrastructurally in order to elucidate their histogenesis. The histological subtypes of this benign fibrous lesion of the visceral pleura, i.e. the cellular, the collagenous, and the hyaline, were separately analysed.
The tumours are composed of undifferentiated mesenchymal cells, intermediate and differentiated fibroblasts as well as collagenous interstitial tissue. The varying distribution of these cell elements account for the various histological subtypes. Morphological similarities between the mesenchymal tumour cells and the superficial mesothelial cells, which are always separated from the true tumour tissue by an intact basement membrane, were not observed.
The different cellular elements can be regarded as parts of a continuous spectrum of cytodifferentiation, in which the mature fibroblasts are derived via intermediate forms from the undifferentiated cells. It is concluded that the localized fibrous tumours of the pleura arise from immature mesenchymal stem cells, which seems to be normally found in the submesothelial layer of the visceral pleura.
During an ultrastructural review of 30 diffuse and 10 localized mesotheliomas, it was apparent that some micrographs showed various stages in the developmental processes involved in the formation of histological patterns in diffuse mesotheliomas and a histogenetic link between diffuse and localized mesotheliomas. Cells in the stromal or sarcomatous regions of diffuse mesothelioma often show varying degrees of mesothelial differentiation and a gradual transition to cells with typical mesothelial characteristics that organize into structures recapitulating the surface layer of serosal membranes. Tumor cells in localized mesotheliomas had many similarities to the stromal cells in the diffuse counterpart including intercellular junctions, rare microvilli and occasional foci of basal lamina. It is postulated that diffuse and localized mesotheliomas share a common histogenetic origin as a result of neoplastic induction of specialized submesothelial cells. In this concept, tumor cells in diffuse mesotheliomas reflect stages in the differentiation and organization of normal serosal membranes and localized mesotheliomas mirror the earliest phases of this process.
Solitary fibrous tumor of the pleura (SFTP) is a rare neoplasm of the pleura. Although an increasing number of case series have been reported in recent years, so far clinical behavior is still unpredictable. The following article presents a detailed review of the recent larger series of SFTP with particular attention to the clinical presentation, pathologic characteristics and surgical features in order to define more precisely the long-term outcome after treatment of this rare entity.
Usually, after a complete surgical resection a very long survival could be expected in almost all cases. However, the preoperative detection and management of malignant SFTPs are still challenging issues.
SFTP remains an enigmatic tumor. Clinical and radiological assessment is often unsatisfactory to obtain a definitive diagnosis. Benign SFTPs are almost always cured with complete surgical resection, and in cases of recurrence the re-do resection of benign recurrences is usually curative. Long-term survivals are also possible for malignant SFTPs, although a higher recurrence rate and higher tumor-related mortality can be expected in these cases. Histologic characteristics distinguishing benign from malignant variants are crucial in estimating the risk of recurrence and planning adjuvant therapies.
Solitary (localized) fibrous tumors of the pleura (SFTP) are rare slow-growing neoplasms that generally have a favorable prognosis. The aim of this paper is to evaluate the predictors of outcome in a series of 110 patients with SFTP.
The records of 110 patients (63 men; mean age 56.4 years; range, 17 to 79) surgically treated for SFTP from July 1990 to February 2008, were evaluated for demographics, operative procedure, histopathology, morbidity, mortality, postoperative chemotherapy or radiotherapy, and long-term follow-up.
Operative mortality was 0.9% (1 of 110) and the overall morbidity was 10.9% (12 of 110). The main surgical approach was video-assisted thoracoscopic surgery (69 procedures with a conversion rate of 14.5%); 40 patients underwent thoracotomy and 1 had sternotomy. The visceral pleura was the site of origin in 95 tumors, the parietal pleura in 13, the mediastinal pleura in 2 cases. Sixty-three tumors were pedunculated, 35 were sessile, and 12 were inverted fibroma. Tumors were pathologically benign in 95 cases (86.4%), and malignant in 15 (13.6%). Symptomatic patients presented with malignant tumors more often than asymptomatic (19.1% versus 9.5%). Overall 10-year survival rate was 97.5%. The overall disease-free survival rate was 90.8% (95.7% in benign cases and 67.1% in malignant cases; p < 0.05). Eight patients presented with recurrence of disease, 4 cases of which were malignant and 4 were benign.
Solitary fibrous tumor of the pleura is a rare disease that includes both benign and malignant variants.The outcome is mostly benign, with an overall 10-year survival rate of 97.5%. Pathologically benign lesions show a better disease-free survival rate than malignant lesions (95.7% versus 67.1%; p < 0.05). Surgery is the gold standard of treatment as neither radiotherapy nor chemotherapy proved to be effective.
Pleuro-pulmonary solitary fibrous tumor (SFT) is a relatively uncommon mesenchymal neoplasm of uncertain histogenesis, unknown molecular features, and unpredictable clinical behavior. Although complete resection is universally accepted as the most important single prognostic factor, some clinicopathologic characteristics (gross appearance, tumor size, mitotic index, tumor necrosis, hypercellularity, and pleomorphism) are related to patient outcome, and a staging system based on these parameters with practical therapeutical implications has been recently proposed by de Perrot et al. Here, 88 pleuro-pulmonary SFTs were collected and clinicopathologic characteristics including de Perrot classification, patients' follow-up, p53 expression, and several "targetable" kinases [c-kit, v-raf murine sarcoma viral oncogene homolog B1, platelet-derived growth factor receptor (PDGFR)-alpha/beta, c-met, epidermal growth factor receptor (EGFR)] were retrospectively analyzed. Fifty-two cases (59%) had at least 1 clinicopathologic feature related to malignancy, whereas mortality and recurrences occurred in 10.2% and 18.2% of the cases, respectively. de Perrot staging and high p53 expression were significantly related to the conventional clinicopathologic prognostic features as well as to overall survival (OS) and disease-free survival (DFS) (P<0.001). At multivariate analysis, high p53 expression and tumor necrosis were the only parameters significantly associated with OS and DFS (P=0.017 and P=0.012, respectively). Immunohistochemical expression was frequently detected for PDGFR-alpha (97.7%), PDGFR-beta (86.5%), and hepatocyte growth factor receptor (96.6%), whereas missense mutations were only identified in 2 cases both involving PDGFR-beta (exons 18 and 20). We conclude that de Perrot stratification of SFT is a reliable prognostic indicator and merits consideration in view of its suggestions for the management of these tumors in daily practice. p53 expression may represent a valid and easy-to-test prognostic factor significantly related to OS and DFS. Although mutations of the corresponding genes are rare events in SFT, PDGFR-alpha/beta, and hepatocyte growth factor receptor tyrosine kinases should be further investigated given the availability of specific inhibitory molecules which might provide useful and novel therapeutical approaches for SFT patients.
In a series of eighteen diffuse malignant mesotheliomas, five cases were encountered in which thoracic surgery with benign nontumorous diagnosis preceded the development of a malignant mesothelioma by several years. The morphological findings in three of these five cases are compared with the morphology of the tumor specimens and an attempt is made to recognize the earliest possible malignant features. Crowding of mesothelial cells, their variability in size and nuclear hyperchromatism are pointed out as warning signs. In relation to these findings, the histogenetic significance of predominantly fibroproliferative versus epithelial-like pleural lesions is discussed. A histogenetic classification, based on the studies of eighteen diffuse malignant mesotheliomas, two benign fibrous mesotheliomas, one pleural fibrosarcoma, and numerous pleural plaques as well as reactive mesothelial lesions, is offered. The therapeutic aspects are mentioned.
Localized pleural mesotheliomas are rare tumors that have a variety of clinical presentations, from an asymptomatic solitary nodule to a massive, highly symptomatic neoplasm filling most of the pleural cavity. Two cases are reported which show the clinical spectrum of the more common benign variant. The clinical differentiation between the benign tumor as well as the less frequent malignant neoplasms of localized mesotheliomas has been disappointing. Complete surgical resection is the preferred treatment for both types and is usually curative with the benign mesothelioma.
Two localized and two diffuse pulmonary mesotheliomas were studied with both light and electron microscopes. The diffuse mesotheliomas showed features and characteristics of mesothelial cells in the electron microscope, whether lining spaces or within solid parts of the tumor. The localized mesothelioma showed predominance of poorly differentiated cells and fibroblasts. The relationship between the localized and diffuse mesotheliomas is not clear, but the former could be a group of variegated tumors. It appears that a definite electron microscopic diagnosis of diffuse pulmonary mesothelioma can be made at least in some of the surgically removed tissues suspected to be diffuse mesothelioma by clinical and light microscopic findings.
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