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Retroperitoneal schwannoma mimicking hepatic tumor

Authors:
Lei Gu at Renji Hospital
Lei Gu
Wei Liu at University of Science and Technology of China
Wei Liu
Qing Xu
Qing Xu
Qing Xu
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Zhi-Yong Wu
Zhi-Yong Wu
Zhi-Yong Wu
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Chinese Medical Journal 2008; 121(17):1751-1752 1751
Case report
Retroperitoneal schwannoma mimicking hepatic tumor
GU Lei, LIU Wei, XU Qing and WU Zhi-yong
Keywords: retroperitoneal schwannoma; hepatic tumor; differential diagnosis
etroperitoneal tumors are difficult to distinguish,
especially because they share common radiological
features with tumors of the liver.1 When we come across
such tumors, the clinical diagnosis is often confusing.
Here, we report a case of retroperitoneal schwannoma
which mimicked a cystic right lobe hepatic tumor.
CASE REPORT
A 72-year-old man underwent CT at a medical check-up
for a 7-day unidentified fever without any discomfort. A
giant cystic tumor (18 cm in diameter) was detected in the
right lobe of the liver (Figures 1 and 2). Blood analysis
showed almost normal liver function. Carcinoembryonic
antigen and alpha-fetoprotein were both negative. No
evidence of tumor was found in the gastrointestinal tract,
which ruled out the possibility of liver metastasis. The
patient underwent laparotomy following preoperative
diagnosis of primary hepatic tumor, possibly a cystic
tumor. At operation, the tumor was found to be 18 cm in
diameter. The tumor originated from the retroperitoneum
and compressed the atrophic right lobe of the liver; it was
therefore diagnosed as being of a retroperitoneal origin.
Then, complete removal of the tumor and partial
hepatectomy was performed.
Figure 1. CT showing a giant cystic mass in the right lobe of the
liver (CT value 11 Hu).
Figure 2. CT in the arterial phase showing enhancement of the
tumor edge (CT value 50 Hu).
Figure 3. Giant retroperitoneal mass with a well-formed
envelope.
Figure 4. Necrosis and liquefaction in the center of the tumor.
The specimen demonstrated a well-circumscribed tumor,
which was 18 cm × 20 cm × 22 cm in size, with a
resected-tumor weight of 3200 g (Figure 3). It was well
encapsulated and round, with a smooth surface and hard
like a stone, and had necrosis and liquefaction in the
center (Figure 4). It was yellowish with a heterogeneous
consistency at the cut surface. The tumor lesions were
separated by fibrous bands and surrounded by an
envelope. Histological examination revealed that the
tumor was composed of densely packed spindle cells with
oval nuclei arranged in wide bands. The nuclei did not
show palisading, and were not uniform in size, but there
was no mitosis (Figure 5). The tumor stained positively
for S-100 (Figure 6), vimentin (Figure 7), CD34 and
CD99.
DISCUSSION
Schwannoma is a well-defined, usually benign, tumor
arising from the nerve sheath (Schwann cells). It may
present as a solitary mass in any part of the body, but is
more commonly seen in the head and neck, the extremities,
and on the trunk.2 It is rarely found in the abdomen,
especially the retroperitoneum. It has a reported incidence
of only 0.5%–1.2%,3 which makes accurate preoperative
diagnosis difficult.4,5 During the normal check-up for an
abdominal mass, ultrasonography is often the first-line
imaging modality, and CT and MRI are both helpful for
diagnosis.6 In particular, the tumor can be located by
digital subtraction angiography, but unfortunately in our
case, the examination was not performed preoperatively.
The primary site of the tumor and its characteristics were
difficult to determine. In the present case, dynamic CT
revealed that the tumor was relatively hypovascular,
which suggested a hypovascular primary liver tumor such
as a scirrhous-type hepatocellular carcinoma or combined
hepatocellular carcinoma and cholangiocellular
carcinoma.
Confirmation of the character of the tumor depends on
the pathology and immunohistochemistry. The positive
expression of S-100 protein is valuable for diagnosis.7
R
Department of General Surgery, Renji Hospital, Shanghai Jiao
Tong University School of Medicine, Shanghai 200127, China (G
u
L, Liu W, Xu Q and Wu ZY)
Correspondence to: Prof. WU Zhi-yong, Department of General
Surgery, Renji Hospital, Shanghai Jiao Tong University School o
f
Medicine, Shanghai 200127, China (Tel: 86-21-68383732. Fax:
86-21-58394262. Email: zhengwk@online.sh.cn)
Chin Med J 2008;121(17):1751-1752
1752
Figure 5. Image of HE staing (Original magnification ×40).
Figure 6. Positive staining of S-100 (Immunohistochemical staining, original magnification ×40).
Figure 7. Positive staining of vimentin (Immunohistochemical staining, original magnification ×10).
Different degrees of S-100 expression in tumor cells can
be the means to differentiate schwannoma from
fibrosarcoma, leiomyosarcoma and angiosarcoma.
Surgical treatment is the only valid option for
schwannoma, because it is not sensitive to radiotherapy
and chemotherapy.8 Recurrence of schwannoma is very
high if resection is not complete. The surgical technique
is very important, such as gentle work, complete removal
with envelope and cauterization to destroy the remaining
tumor. The drawback of operation is mass bleeding,
because of the abundant blood vessels in the core of the
tumor and compression of adjacent blood vessels.9
Despite the giant size of the tumor in this case, we still
removed it perfectly. The patient recovered uneventfully
and was discharged, and is still in follow-up. We will take
stock of the prognosis in the near future.
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(Received December 28, 2007)
Edited by HAO Xiu-yuan
... The cystic schwannomas tend to be larger, with a mean diameter of 10.5cm. Total tumour excision is the treatment of choice for presacral Schwannoma [4,11], as malignant schwannomas are insensitive to chemotherapy and radiation, resulting in poor prognosis [12]. Generally anterior trans-abdominal or retroperitoneal approach for presacral Schwannoma to gain control of vascular plexus and protection of intrapelvic organs. ...
... Generally anterior trans-abdominal or retroperitoneal approach for presacral Schwannoma to gain control of vascular plexus and protection of intrapelvic organs. Some authors believe that complete resection is ideal and sacrificing of vital structures may be necessaryto achieve negative margins [11]. In patients who underwent partial resection, some investigators have even reported recurrence rates of up to 10-20% even in benign circumstances, thus emphasizing the importance of a complete resection [7]. ...
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... Given their benign nature, schwannomas in the retroperitoneum (as with many other locations) are usually incidental radiographic findings in the process of investigating another unrelated etiology. There are multiple cases in the literature in which retroperitoneal schwannomas have been identified incidentally mimicking other tumors such as hepatic tumors, adrenal tumors, and ovarian neoplasm in women [10][11][12][13]. Similar to this patient's case, there are also cases of retroperitoneal schwannomas mimicking metastatic diseases, such as one case of a schwannoma mimicking necrotic lymph node metastasis from bladder cancer and another case of a schwannoma mimicking lymph node metastasis of seminoma [14,15]. ...
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Schwannomas are rare benign tumors that are often asymptomatic and identified incidentally on imaging studies undertaken for another purpose. Schwannomas arising from the vestibular nerve are the most common site of identification; however, schwannomas can arise extracranially in any peripheral nerve tissue. Here, we present a case study of a patient with a localized rectal adenocarcinoma who was found to have a retroperitoneal schwannoma initially felt to be a lymph node metastasis of his rectal cancer. The diagnosis of schwannoma was confirmed via biopsy, which resulted in changes to the patient's overall management including radiotherapy volumes and recommendation against neoadjuvant or adjuvant systemic therapy.
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... Therefore, a definitive diagnosis of schwannoma should be made on postoperative histopathology [5,9]. Schwannomas are not sensitive to radiotherapy and chemotherapy, the only valid treatment is complete surgical excision [10]. However, controversy exists over the necessity of negative soft-tissue margins especially when adjacent tissue or viscera need to be sacrificed. ...
Retroperitoneal shwannoma: A case report
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Full-text available
  • Sep 2021
Introduction Schwannomas are tumors that arise from Schwann cells of the peripheral nerve sheath and rarely occur in the retroperitoneum (3% of all schwannomas). Patients are usually asymptomatic or have nonspecific symptoms, making accurate preoperative diagnosis difficult. Schwannomas are usually benign, but infrequently undergo malignant transformation. Herein, we report a case of retroperitoneal schwannoma and review the relevant literature. Presentation of case A 25-year-old woman presented to our department with a 2-year history of abdominal pain that was localized in the right flank without radiation, constipation/diarrhea or externalized digestive hemorrhage. On physical examination, we found a painless palpable mass in the right hypochondrium extending to the right iliac fossa, measuring approximately 10 cm. The MRI and CT scan showed the presence of a large intra-abdominal oval formation in the right para-umbilical region. It was well limited, measuring 110*69mm with discrete irregular contours, thickened wall and heterogeneous content mostly fluid. They also showed the presence of a cystic formation in the right ovary measuring 84*52mm and extending over 76mm. The procedure consisted of resection of the retroperitoneal solid cystic mass, right ovariectomy and drainage of the right parietal-colic gutter by Salem sump tube. A laparotomy with a median incision above and below the umbilicus was performed. After the resection, the specimens were sent for anatomopathological examination which concluded that the retroperitoneal mass was a schwannoma and the ovarian mass was a serous cystadenoma. Discussion Retroperitoneal schwannomas are rare tumors and a pre-operative diagnosis is often difficult. The diagnosis is most often fortuitous and late, given the latency of the tumor's evolution, and the definitive diagnosis is based on histopathologic examination. Herein we presented a case of retroperitoneal schwannoma and studied the features of this phenomenon on the basis of the literature. Conclusion Retroperitoneal schwannomas are rare. The diagnosis is often late at the stage of a large tumor. Radiologic findings are usually nondiagnostic. The treatment of choice is complete surgical excision. Prognosis is good but because of the risk of recurrence and malignant transformation, further follow-up is necessary.
View
... Recurrence of benign schwannoma is rare, it follows usually incomplete resection, which was reported in 5%-10% of cases [17]. In case of recurrence, surgical excision is recommended. ...
Retroperitoneal Schwannoma: Two Rare Case Reports
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  • Feb 2021
Schwannomas are neuroectodermal tumors that rarely occur in the retroperitoneal space. We report two cases of patients who presented with abdominal pain. Radiological findings revealed a retroperitoneal mass in both cases. Both patients underwent complete surgical excision with an uneventful postoperative course. The histopathological study confirmed the nature of schwannoma. Complete surgical excision remains the gold standard for the management of these tumors. The preoperative diagnosis is usually difficult; however, the definitive diagnosis is made upon histopathological examination.
View
... The prognosis of this disease is good, and postoperative complications are rare, the most common is recurrence (5-10%), which is related to the rupture or incomplete resection of the tumor (26). The importance of complete resection is, therefore, emphasized (27). Because of its insensitivity to radiation and chemotherapy, re-surgical resection is recommended for recurrent schwannoma (28). ...
Clinical Characteristics and Treatment Strategy of Retroperitoneal Schwannoma Adjacent to Important Abdominal Vessels: Three Case Reports and Literature Review
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Full-text available
  • Jan 2021
Purpose: The purpose of this study was to review the clinical characteristics and treatment strategies of patients with retroperitoneal schwannomas adjacent to important abdominal vessels. Case Presentation: A total of three patients with retroperitoneal schwannoma immediately adjacent to important blood vessels in the abdominal cavity underwent successful surgical resection. They all had symptoms of abdominal pain and discomfort, two cases underwent three-dimensional reconstruction. There were no serious complications such as peripheral blood vessels and organ damage in all three cases. One case had chyle leakage after surgery, conservative treatment was successfully discharged. Conclusions: Retroperitoneal schwannomas immediately adjacent to important abdominal vessels have unique clinical characteristics. Preoperative three-dimensional reconstruction can fully show the local vascular relationship of the tumor, which is conducive to surgical planning and risk assessment. Benign tumors with large size and adjacent complex vessels can still be completely resected by surgery. Laparotomy resection is safe and feasible.
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... [3] Complete local excision or simple enucleation may be contemplated as the treatment of choice because benign schwannomas almost never transform to malignant ones. [4,5] Rare benign tumors such as schwannomas may be found out incidentally, without any specific symptoms. Limited cases of laparoscopic approach to a retroperitoneal schwannoma located beside the vital organs and great vessels have been reported so far. ...
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Laparoscopic resection of a retroperitoneal schwannoma posterior to the renal artery
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Introduction Retroperitoneal schwannoma is usually asymptomatic, and is often found incidentally during physical examination. It is easy to be misdiagnosed as paraganglioma, retroperitoneal malignant tumor and giant lymphocyte hyperplasia. Accurate preoperative diagnosis is helpful for clinicians to make surgical plans and preoperative preparations. This paper reports a case of retroperitoneal schwannoma. Preoperative imaging suggested a neurogenic tumor behind the left renal artery. The treatment was laparoscopic retroperitoneal tumor resection. The postoperative pathological diagnosis was retroperitoneal schwannoma. Case presentation The 52-year-old female patient was admitted to the hospital due to a left retroperitoneal tumor. Preoperative CT and MRI showed neurogenic tumor. After patient authorization, left retroperitoneal tumor resection was performed under laparoscopy. The postoperative pathological diagnosis was retroperitoneal schwannoma. The patient was followed up for 1 year without recurrence or metastasis. Clinical discussion The CT features of retroperitoneal schwannoma may be lower than that of the muscle tissue at the same level, with uneven density, cystic lesions, hemorrhage, calcification and other characteristics. Enhanced CT can show progressive enhancement, mild to moderate enhancement in the arterial phase and moderate enhancement in the delayed phase. MRI showed slightly high signal intensity in the center of T2WI lesions, obvious high signal intensity at the edge, and high signal intensity on DWI. The diagnosis of retroperitoneal schwannoma depends on postoperative pathological examination. S-100 protein is one of its specific markers, and most of them are positive. Retroperitoneal schwannoma is mostly benign, but there are also some patients with malignant tumors. The first choice of treatment is complete resection of the tumor, and the tumor margin can also be negative by removing part of the normal adjacent tissue. The survival rate of patients with complete resection can reach 100 %, and the recurrence rate of patients with incomplete resection is about 5–10 %. Conclusion Retroperitoneal schwannoma is a relatively rare retroperitoneal tumor. Enhanced CT can show progressive enhancement, mild to moderate enhancement in the arterial phase and moderate enhancement in the delayed phase. MRI showed slightly high signal intensity in the center of T2WI lesions, obvious high signal intensity at the edge, and high signal intensity on DWI. The diagnosis of retroperitoneal schwannoma depends on postoperative pathological examination, and S-100 protein is one of its specific markers. Retroperitoneal schwannoma is mostly benign, but there are also some malignant tumors. The treatment of retroperitoneal schwannoma is the first choice to completely remove the tumor.
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Imaging of ancient schwannoma. AJR Am J Roentgenol
Article
Full-text available
  • Sep 2004
We surveyed the clinical symptoms and radiologic features of ancient schwannoma, a rare variant of schwannoma characterized by degenerative changes. We present the clinical, radiologic, and pathologic features in seven patients with ancient schwannoma (mean age, 62 years; range, 45-80 years) treated at our department between 1998 and 2003. The most characteristic clinical features were a sign like Tinel's sign and a long interval between the onset of symptoms and surgery (mean interval, 8.3 years). Ancient schwannomas can grow large; the biggest tumor seen in our study was 14 cm long. The highly accurate radiologic assessment made possible with contrast-enhanced MRI and CT scanning showed enhancement at a peridegenerative area and sometimes at a capsule. These findings differ from those of the typical schwannoma and neurofibroma patterns reported to date. Furthermore, bone scintigraphy showed uptake in the tumor, but no accumulation was seen on gallium-67 citrate scintigraphy. The characteristic clinical and radiologic findings of ancient schwannoma should make it possible to differentiate it from malignant tumors.
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Imaging of ancient schwannoma
Article
  • Aug 2004
OBJECTIVE. We surveyed the clinical symptoms and radiologic features of ancient schwannoma, a rare variant of schwannoma characterized by degenerative changes. MATERIALS AND METHODS. We present the clinical, radiologic, and pathologic features in seven patients with ancient schwannoma (mean age, 62 years; range, 45-80 years) treated at our department between 1998 and 2003. RESULTS. The most characteristic clinical features were a sign like Tinel's sign and a long interval between the onset of symptoms and surgery (mean interval, 8.3 years). Ancient schwannomas can grow large; the biggest tumor seen in our study was 14 cm long. The highly accurate radiologic assessment made possible with contrast-enhanced MRI and CT scanning showed enhancement at a peridegenerative area and sometimes at a capsule. These findings differ from those of the typical schwannoma and neurofibroma patterns reported to date. Furthermore, bone scintigraphy showed uptake in the tumor, but no accumulation was seen on gallium-67 citrate scintigraphy. CONCLUSION. The characteristic clinical and radiologic findings of ancient schwannoma should make it possible to differentiate it from malignant tumors.
View
Perineurial Malignant Peripheral Nerve Sheath Tumor (MPNST)
Article
  • Nov 1998
  • AM J SURG PATHOL
Most malignant peripheral nerve sheath tumors (MPNST) are schwannian in nature. The pathologic features of MPNST with perineurial cell differentiation remain to be characterized. To determine the clinicopathologic, immunohistochemical, and ultrastructural characteristics of perineurial MPNST, 121 MPNST from the Mayo Clinic Tissue Registry were examined. Of these 23 spindle cell tumors with long processes disposed in whorls or storiform patterns, features typical of perineurioma, were studied. On the basis of immunohistochemistry (epithelial membrane antigen+/S-100-), 5 perineurial MPNST were identified among 23 tumors selected. These and two previously characterized perineurial MPNST are the subject of this study. None of seven tumors was associated with NF-1. Patients included five males and two females ranging in age from 11 to 83 years (mean, 45.7 years). The tumors measured 1.5 to 30 cm (mean, 9.1 cm) and arose in the extremities (two), trunk (two), face (one), mediastinum (one), and retroperitoneum (one). Only one tumor was nerve associated (phrenic nerve). All tumors were surgically removed. No encapsulation or neurofibroma components were noted. Necrosis was seen in three lesions. Four tumors were classified as high-grade malignant and three as low grade. Mitotic indices varied from 1 to 85/10 high-power fields (median, 16). Immunoreactivities included epithelial membrane antigen (100%), vimentin (100%), Leu-7 (57%), and CD34 (14%). Stains for S-100 protein, muscle markers, and cytokeratin were nonreactive. Ultrastructurally, perineurial-like cells were noted in three tumors and cells intermediate between perineurial and Schwann cells in one. Four tumors recurred and two metastasized; no deaths of disease were noted at follow-ups of 28 to 98 months (mean, 66.9). In conclusion, 4% of MPNST show perineurial cell differentiation. An NF-1 association has yet to be described. Nerve involvement is infrequent. Their immunophenotype (epithelial membrane antigen+/S-100-) frequently indicates ultrastructural perineurial differentiation. The prognosis of perineural MPNST appears to be more favorable than that of conventional MPNST.
View
Benign Retroperitoneal Schwannoma
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  • Feb 1992
A rare case of benign retroperitoneal schwannoma in a 76-year-old man is reported. Ultrasound and computerized tomography disclosed two cystic retroperitoneal tumors sized 12 cm and 7 cm. The larger tumor was located anterior to psoas muscle and the smaller one was within the muscle. The larger tumor was excised via laparotomy. After 3.5 years follow-up the intramuscular tumor has remained unchanged and the patient has no symptoms.
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[X-ray computed tomography in the diagnosis of peritoneal and retroperitoneal neoplasms]
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  • Chung Hua Hsueh Tsa Chih
CT findings of peritoneal and retroperitoneal neoplasms were evaluated in 24 patients. The accuracy of CT in locating peritoneal and retroperitoneal tumors was 87% and in differentiating benign from malignant ones 96%. It is difficult to evaluate the tumors histopathologically. We suggest that CT scan be preferable in diagnosis of tumors in that area.
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Malignant peripheral nerve sheath tumour with vascular differentiation: A report of four cases
Article
  • Jun 1996
Four cases of malignant peripheral nerve sheath tumour showing vascular differentiation are described. One case was associated with neurofibromatosis 1 and contained angiosarcomatous, cartilaginous and rhabdomyoblastic elements. The other cases occurred in patients without neurofibromatosis and showed a spectrum of vascular lesions ranging from lobulated, haemangioma-like structures to angiosarcoma. These are the first recorded examples of this phenomenon not associated with neurofibromatosis. Immunohistochemical examination demonstrated the endothelial nature of the lesions in all cases and revealed cells positive for alpha-smooth muscle actin, probably pericytes, closely apposed to the endothelium.
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Schwannoma of the liver: Report of two surgical cases
Article
  • Sep 1998
Two surgical cases of benign schwannoma of the liver were examined: A 64-year-old female who was admitted to hospital for the treatment of early gastric cancer (case 1) and a 69-year-old female who had pitting edema in the legs (case 2). Diagnostic imaging revealed large solid masses located in the caudate lobe through to the left lobe of the liver in case 1 and in the left lobe in case 2. Both patients showed no signs of von Recklinghausen's disease. Partial hepatectomies were performed and the maximum diameter of their resected hepatic tumors was 4 cm and 15 cm, respectively. Histologically, the well-demarcated tumors were yellowish in color, elastic-hard in consistency and consisted predominantly of short spindle-shaped cells proliferating in an interlacing fashion. The tumor lesions were separated by fibrous bands and surrounded by a lymphoid cuff. Immunohistochemically, the tumor cells were positive for S-100 protein. The tumors were diagnosed as benign hepatic schwannoma.
View
Perineurial malignant peripheral nerve sheath tumor (MPNST): A clinicopathologic, immunohistochemical, and ultrastructural study of seven cases
Article
  • Dec 1998
  • AM J SURG PATHOL
Most malignant peripheral nerve sheath tumors (MPNST) are schwannian in nature. The pathologic features of MPNST with perineurial cell differentiation remain to be characterized. To determine the clinicopathologic, immunohistochemical, and ultrastructural characteristics of perineurial MPNST, 121 MPNST from the Mayo Clinic Tissue Registry were examined. Of these 23 spindle cell tumors with long processes disposed in whorls or storiform patterns, features typical of perineurioma, were studied. On the basis of immunohistochemistry (epithelial membrane antigen+/S-100-), 5 perineurial MPNST were identified among 23 tumors selected. These and two previously characterized perineurial MPNST are the subject of this study. None of seven tumors was associated with NF-1. Patients included five males and two females ranging in age from 11 to 83 years (mean, 45.7 years). The tumors measured 1.5 to 30 cm (mean, 9.1 cm) and arose in the extremities (two), trunk (two), face (one), mediastinum (one), and retroperitoneum (one). Only one tumor was nerve associated (phrenic nerve). All tumors were surgically removed. No encapsulation or neurofibroma components were noted. Necrosis was seen in three lesions. Four tumors were classified as high-grade malignant and three as low grade. Mitotic indices varied from 1 to 85/10 high-power fields (median, 16). Immunoreactivities included epithelial membrane antigen (100%), vimentin (100%), Leu-7 (57%), and CD34 (14%). Stains for S-100 protein, muscle markers, and cytokeratin were nonreactive. Ultrastructurally, perineurial-like cells were noted in three tumors and cells intermediate between perineurial and Schwann cells in one. Four tumors recurred and two metastasized; no deaths of disease were noted at follow-ups of 28 to 98 months (mean, 66.9). In conclusion, 4% of MPNST show perineurial cell differentiation. An NF-1 association has yet to be described. Nerve involvement is infrequent. Their immunophenotype (epithelial membrane antigen+/S-100-) frequently indicates ultrastructural perineurial differentiation. The prognosis of perineural MPNST appears to be more favorable than that of conventional MPNST.
View
Neurilemmoma of the diaphragm mimicking a liver tumor: Case report
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  • Oct 2004
A 47-year-old male with a solid, previously cystic tumor in the subphrenic part of the liver consulted for surgery. Laparotomy showed a well-circumscribed tumor originating from the diaphragm, which made a significant depression in the liver. Complete removal of the tumor was achieved. Pathologic examination led to a diagnosis of neurilemmoma originating from the diaphragm.
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Extrahepatic bile duct neurilemmoma mimicking Klatskin tumor
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  • May 2007
Neurilemmoma rarely develops in the biliary tree. Here, we report a 39-year-old Iranian woman with neurilemmoma in the extrahepatic bile duct presenting with progressively deepening jaundice. On the basis of clinical and radiological features, this tumor was initially suspected as Klatskin tumor. Histologically, the tumor was a typical neurilemmoma. Immunostaining showed that tumor cells were strongly and diffusely positive for S-100 protein, which supported the diagnosis of neurilemmoma. Neurilemmoma should be considered in the differential diagnosis of obstructive jaundice.
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