Case Report
Intraosseous malignant peripheral nerve sheath tumor with focal epithelioid differentiation of the thoracic spine Naohisa Miyakoshi, Yuji Nishikawa*, Yoichi Shimada, Kyoji Okada, Masayuki Yoshida*, Katsuhiko Enomoto*, Eiji Itoi
m o fr strongly positive d for S-100 and do not form s protein a glandular or cystic structures. It is estimated that 5% or n lobelongtioto this group. fewer MPNSTs n In this report, we a present a rare case of MPNST arising
w c from the intraosseous i o l region of the thoracic spine. The
case d report isbthe first documentation of intraosseous
upeculiar MPNST with biphasic differentiation occurring
ethe spinal . P e in column.
) fr w m r fo kno .co Case Report
w healthy 75-year-old woman presented with
le ed A previously o b two-week of severe back pain, progressive n history la M dahypesthesia k i and motor weakness of both legs. The a by e magnetic resonance imaging (MRI) of the thoracic spine v that an ill-defined epidural mass arising from a d .m revealed the intraosseous of the posterior element of the T7 is te w vertebra severelylesion compressed the spinal cord [Figure 1A F os w D]. A metastatic spinal lesion was mostly suspected but D w h extensive radiographic examinations including total body ( P te computed tomography scan revealed no evidence of other s si i primary neoplasms. Due to progressive paraplegia, the h patient underwent emergency decompression surgery one T a day after the admission. The lesion involved the lamina,
Departments of Orthopedic Surgery and *Pathology and Immunology, Akita University School of Medicine, Akita 010-8543, Japan
The authors describe an extremely rare case with malignant peripheral nerve sheath tumor (MPNST) with focal epithelioid differentiation presenting as an intraosseous lesion of the spine. A 75-year-old woman presented with progressive paraplegia caused by epidural mass arising from the posterior element of the T7 vertebra. At surgery, the lesion was noted to originate from the T7 vertebra and separate from the dura and spinal nerve roots. The patient died of tumor metastases to the lungs six
months after the initial presentation. Histological diagnosis was MPNST. However, the tumor also contained cystic
structures lined by epithelioid cells, requiring differentiation from synovial sarcoma. From the histological and immunohistochemical features, as well as the absence of SYT-SSX fusion gene expression, the diagnosis of MPNST with focal epithelioid differentiation was made. This is the first case report of intraosseous MPNST of the spine with a peculiar biphasic appearance.
[7]
Key words: Epithelioid differentiation, intraosseous tumor, malignant peripheral nerve sheath tumor, spine
Introduction Malignant peripheral nerve sheath tumor (MPNST) of the spine is a rare spinal tumor and its rate among primary spinal tumors of Schwann cell origin was reported to be 2-3%.[1,2] The spinal MPNSTs usually arise from spinal nerve roots and cause secondary bony changes. Intraosseous MPNST is extremely rare and to the best of our knowledge, only two such cases in the spine have been reported in the literature.[3,4] Aberrant epithelial or epithelioid differentiation in MPNSTs is rare but well-recognized.[5-7] Epithelioid MPNST is defined as a tumor predominantly composed of large epithelioid cells and in most cases, they are
right pedicle and bilateral transverse processes. The epidural tumor was thoroughly resected and the posterior stabilization was performed using the Luque titanium rods with sublaminar cables. The epidural tumor was easily detached from the dura. Bilateral T7 spinal roots were identified separate from the tumor mass. The postoperative histological diagnosis was MPNST. Postoperatively, the symptoms of the patient were relieved dramatically. However, the patient’s symptoms recurred in six weeks postoperatively. The tumor grew rapidly thereafter despite local radiotherapy [Figure 2A-B]. Six months after the initial clinical presentation, the patient died from respiratory failure due to direct invasion of the mass into the thorax and multiple lung metastases.
Naohisa Miyakoshi Department of Orthopedic Surgery, Akita University School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan. E-mail:
[email protected]
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Miyakoshi et al. : Intraosseous MPNST of the spine
A C
rhabdomyoblastic features, such as cross striations. Cystic spaces containing serous fluid were scattered within the tumor and some of the spaces formed malignant cystic or glandular structures lined by epithelioid cells with marked nuclear atypia [Figure 3C]. Both spindle and epithelioid tumor cells were strongly positive for vimentin. Nuclei of some spindle cells were faintly positive for S 100 protein [Figure 3D]. The epithelioid cells lining the cystic spaces and adjacent spindle cells were occasionally weakly positive for AE1/AE3 and CAM5.2 but they were negative for epithelial membrane antigen and chromogranin A. The tumor cells were negative for αsmooth muscle actin, desmin, CD31, CD34 and HMB-45. The percentage of MIB-1-positive nuclei to all nuclei was 38%. The SYT-SSX fusion genes, which are specific to synovial sarcoma, were not detected by reverse transcription-polymerase chain reaction using RNA isolated from the tumor tissue. From these histological, immunohistochemical and cytogenetic findings, we finally diagnosed this tumor as MPNST with focal epithelioid differentiation. The diagnosis was approved by an experienced pathologist in this field in an independent institute. The metastatic tumors in the lungs consisted of sheets of spindle cells similar to those seen in the primary tumor.
m o fr d ns a lo tio n w lica o d ub e rf e w P m). r fo kno .co le ed ow Discussion b n li a M dkMPNSTs are relatively uncommon tumors of cells of a by e peripheral nerve v sheath origin. Secondary infiltration a d .m of bone is a well-recognized feature, but primary
MPNSTs appear to be extremely rare. To the is te w intraosseous best of our knowledge, only two cases with primary F os w intraosseous MPNST of the spine have been reported in D the literature. Khan et al reported intraosseous
P te h (w MPNST that arose in the C2 vertebra of a 40-year-old si si woman. The patient underwent tumor excision and stabilization of the cervical spine, but died of pulmonary Th a metastases one year later. Gnanalinghan et al reported a B
D
Figure 1: MRI of the thoracic spine taken at the time of admission demonstrating a destructive lesion arising from posterior element of the T7 vertebra. The spinal cord is severely compressed by extradural extension of the lesion showing intermediate signal intensity on T1weighted and high signal intensity on T2-weighted images. (A) sagittal T1 image; (B) sagittal T2 image; (C) axial T1 image; and (D) axial T2 image
[1,3]
[8,9]
[3,4]
[4]
[3]
A
B
Figure 2: MRI of the thoracic spine taken five months after the surgery showing a giant recurrent tumor of the spine. The tumor mainly expanded posteriorly and occupied the entire length of the instrumented rods. The tumor also infiltrated into the entire T7 and adjacent vertebrae with extension into the thorax. (A) sagittal T1 image; and (B) axial T1 image
Autopsy was performed to reconfirm the previous histological diagnosis. Histologically, the primary tumor consisted of sheets of tumor cells with alternating areas of hyper- and hypocellularity [Figure 3A]. The majority of the tumor cells were atypical spindle cells arranged in vague fascicles [Figure 3B]. Although some tumor cells had abundant eosinophilic cytoplasm, there was no evidence of Neurology India | January-March 2007 | Vol 55 | Issue 1
59-year-old woman with intraosseous MPNST of the T3 vertebra causing spinal cord compression. The patient underwent decompression surgery with spinal instrumentation and survived at one-year follow-up despite developing metastatic deposits in the spine and femur.[3] In general, the prognosis of primary spinal involvement of MPNSTs is not good. These lesions usually arise from the spinal nerve roots and cause secondary bony changes (MPNSTs at paraspinal regions are a known entity).[8,9] Their one-year and five-year survival rates were 76% and 23%, respectively.[1] Local recurrence occurs in 71% of cases.[1] Metastases, most often to the lung, were reported in 33%.[1] The present case with intraosseous spinal MPNST with neurological deficit was characterized by a more dismal clinical outcome. Incomplete removal of the tumor with microscopic spread and ineffectiveness of 65 CMYK65
Miyakoshi et al. : Intraosseous MPNST of the spine
A
C
m o fr d ns a lo tio n a w c i do ubl e P ). e radiation resulted in poorer prognosis in this case. fr References w m r Complete en-bloc resection is impossible for intraosseous o no .co spinal MPNST like the present case because of the diffuse f k w tumoral infiltration into the bone and extraduralle space. d The intraosseous primitivity of a nerve sheath is btumor ea no a undoubted when, in the absence of a relationship with l i y Mthe dk nerve trunk, radiographically and macroscopically a v bthe bone e tumor lies wholly within a bone. However, a involvement when extensive like the present and m d casespinal . s intraosseous e the previously reported two cases iwith t as primary w or s MPNST, cannot be surelyF recognized w oreportedw cases, secondary. Similarly as theD previously h ( in the the diagnosis of primary intraosseous MPNST P e t present case was made intraoperative of i from thefindings is withoriginate the lesion that washnoted to s vertebral T from thea dura and spinal nerve roots. bone and separate D
B
Figure 3: Photomicrographs of the primary tumor. The tumor consisted of sheets of atypical spindle cells with alternating areas of hyper- and hypocellularity (A and B: H/E, original magnifications 20× and 100×, respectively). Cystic spaces containing serous fluid were scattered within the tumor and some of the spaces were lined by epithelioid cells with marked nuclear atypia (C: H/E, 200x). Nuclei of some spindle cells were positive for S-100 protein (D: 400x)
1.
[3,4]
[3,4]
Histologically, divergent differentiation in MPNST occurs in approximately 15% of cases.[10] The epithelioid feature of the tumor in our case required us to differentiate it from sarcomas with biphasic differentiation, especially synovial sarcoma, which may originate from the spines or paraspinal regions. Morrison et al[11] described a rare case of paraspinal synovial sarcoma containing multiple cystic structures. However, in the present case, the histopathological diagnosis of MPNST was favored because of our findings of the histological features with alternating areas of hyper- and hypocellularity, focal positivity for S-100 protein and the absence of expression of the SYT-SSX fusion gene. The present case is the first reported case with intraosseous MPNST of the spine with aberrant epithelioid differentiation.
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Celli P, Cervoni L, Tarantino R, Fortuna A. Primary spinal malignant schwannomas: Clinical and prognostic remarks. Acta Neurochir (Wien) 1995;135:52-5. 2. Seppala MT, Haltia MJ. Spinal malignant nerve-sheath tumor or cellular schwannoma? A striking difference in prognosis. J Neurosurg 1993;79:528-32. 3. Gnanalingham K, Bhattacharjee S, O’Neill K. Intraosseous malignant peripheral nerve sheath tumor (MPNST) of the thoracic spine: A rare cause of spinal cord compression. Spine 2004;29:E402-5. 4. Khan RJ, Asgher J, Sohail MT, Chughtai AS. Primary intraosseous malignant peripheral nerve sheath tumor: A case report and review of the literature. Pathology 1998;30:237-41. 5. Laskin WB, Weiss SW, Bratthauer GL. Epithelioid variant of malignant peripheral nerve sheath tumor (malignant epithelioid schwannoma). Am J Surg Pathol 1991;15:1136-45. 6. Lodding P, Kindblom LG, Angervall L. Epithelioid malignant schwannoma. A study of 14 cases. Virchows Arch A Pathol Anat Histopathol 1986;409:433-51. 7. Weiss SW, Goldblum JR, editors. Enzinger and Weiss’s soft tissue tumors. 4th ed. Mosby: St. Louis (MO); 2001. 8. Kourea HP, Bilsky MH, Leung DH, Lewis JJ, Woodruff JM. Subdiaphragmatic and intrathoracic paraspinal malignant peripheral nerve sheath tumors: A clinicopathologic study of 25 patients and 26 tumors. Cancer 1998;82:2191-203. 9. Collia Fernandez F, Munoz Gonzalez JE, Santos-Briz A, Fernandez Melcon ML, del Valle Manteca A, Diaz Aramendi A. Malignant epithelioid paravertebral schwannoma. Med Clin (Barc) 1980;75:27-31. 10. Ducatman BS, Scheithauer BW. Malignant peripheral nerve sheath tumors with divergent differentiation. Cancer 1984;54:1049-57. 11. Morrison C, Wakely PE Jr, Ashman CJ, Lemley D, Theil K. Cystic synovial sarcoma. Ann Diagn Pathol 2001;5:48-56. Accepted on 26-07-2006
Source of Support: Nil, Conflict of Interest: None declared.
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