Indian Journal of Pathology and Microbiology

: 2015  |  Volume : 58  |  Issue : 4  |  Page : 560--562

An extraneural primary anaplastic ependymoma at the subcutaneous inguinal region: Report of a rare case

Hamide Sayar1, Ayca Ersen2, Neslihan Kurtul3, Mehmet Fatih Yazar4, Ozan Balakan5,  
1 Department of Pathology, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey
2 Department of Pathology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
3 Department of Radiation Oncology, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey
4 Department of General Surgery, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey
5 Department of Medical Oncology, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey

Correspondence Address:
Dr. Hamide Sayar
Department of Pathology, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Avsar Kampusu (TR-46000) Kahramanmaras


Ependymomas commonly arise in the central nervous system. Extraneural presentation is quite rare. Herein, we describe a primary extraneural ependymoma in a young female. The mass was located in the right inguinal area. The cut surface of the 7.5 mm × 6.5 mm × 4.5 mm sized tumor was brownish-yellow in color. Histologically, it was hypercellular exhibiting pseudorosette or rosette formations and some papillary structures. Mitosis was counted as high as 10 per 10 high power fields. Neither necrosis nor vascular endothelial proliferation within the tumor was observed. Tumor cells showed strong glial fibrillary acidic protein immunoreactivity. On epithelial membrane antigen, intracytoplasmic dot-like immunostaining was observed. This is the first report presenting a primary extraneural anaplastic ependymoma arising in the inguinal subcutaneous region.

How to cite this article:
Sayar H, Ersen A, Kurtul N, Yazar MF, Balakan O. An extraneural primary anaplastic ependymoma at the subcutaneous inguinal region: Report of a rare case.Indian J Pathol Microbiol 2015;58:560-562

How to cite this URL:
Sayar H, Ersen A, Kurtul N, Yazar MF, Balakan O. An extraneural primary anaplastic ependymoma at the subcutaneous inguinal region: Report of a rare case. Indian J Pathol Microbiol [serial online] 2015 [cited 2021 Jul 25 ];58:560-562
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Full Text


Ependymal tumors, with the ependymomas being most common, account for 2% of tumors primarily arising in the central nervous system (CNS).[1] They most commonly arise from the ventricular system and/or the central canal of the spinal cord.[2] On the other hand, they rarely occur outside the CNS where they are called as extraneural ependymomas.[3] The majority of primary extraneural ependymomas are seen in the sacrococcygeal subcutaneous tissue and paraovarian area, but they have also been reported in the extraovarian pelvic region and more infrequently in other sites.[4],[5]

Herein, we present a primary extraneural anaplastic ependymoma arising in the inguinal subcutaneous tissue in a young female patient. To our knowledge, this is the first reported case of a primary extraneural anaplastic ependymoma at this site.

 Case Report

A 23-year-old female patient admitted to Kahramanmaras Sutcu Imam University, Department of Surgery, complaining of swelling in the right inguinal region. She had a history of an operation due to an inguinal hernia at this site 10 years ago. Three years ago she had a trauma at the same site. Afterward, pain and swelling were encountered. On physical examination, a round, firm, tender, totally mobile nodule was discovered in the right inguinal region. Ultrasonography revealed a well-confined hypoechoic, heterogenous solid mass; 75 mm × 35 mm in diameter. After obtaining informed consent, the patient underwent an operation of gross total excision of the mass which was just under the skin and over the fascia, with no connection to them [Figure 1]. Macroscopically, the tumor had a well -defined, and lobulated contour [Figure 2]a. It was a solid mass with a grey-tan and brown cut surface. Areas of hemorrhage were observed. Microscopic examination on hematoxylin-eosin stain revealed a hypercellular neoplasm consisting of papillary structures and perivascular pseudorosettes [Figure 2]b,[Figure 2]c,[Figure 2]d. The tumoral cells were low columnar and cuboidal with round to oval nuclei, vesicular to pale granular chromatin pattern, small and prominent central nucleoli. The tumor was encapsulated by intact fibrous tissue. There was moderate nuclear atypia and the mitotic count was focally 10/10 HPF. Vascular endothelial proliferation and tumor necrosis were not seen. In the immunohistochemical study, tumor cells had strong glial fibrillary acidic protein (GFAP) [Figure 2]d immunoreactivity in their cytoplasm. Epithelial membrane antigen (EMA) showed a paranuclear dot-like immunostaining [Figure 2]e. The tumor cells were negative for CK7. The Ki-67 proliferation index was counted as 10% [Figure 2]f. Based on the morphological and immunohistochemical findings; the tumor was reported as "Extraneural anaplastic ependymoma." The postoperative course was uneventful. The patient did not receive any adjuvant therapy and currently is on a close follow-up.{Figure 1}{Figure 2}


Ependymoma mostly arise in the brain and spinal cord. There are rare extraneural cases, most of which are in close relationship with neural axis, reported in the literature.[5],[6] We report an extraneural anaplastic ependymoma localized in the inguinal subcutaneous region. To our knowledge, this localization has not been reported for any extraneural ependymomas before. The extraneural ependymomas are thought to be derived from embryonal rests in the paracoccygeal area. There are also hypothesis that the pelvic ones might be arising from ectopic glial cells or might be neometaplasia of the peritoneal mesenchymal tissue.[7]

There are some reported cases of intracranial ependymomas metastasized to lymph nodes.[5] In our case, to roll out the possibility of any lymph node metastasis; the whole tissue has been sampled and no remnant of any lymphoid tissue was found. The patient has also been screened radiologically by magnetic resonance imaging for any intracranial or spinal mass, by ultrasonography for any pelvic mass, and no tumor was detected. Eventually, we decided that the inguinal area was the primary site for this particular example. This region is not an expected area for any possible ependymal embryonic rests. However, there are hypothesis of possible congenital ectopic glial tissues in different sites of the body.[4],[7] The previous surgery or the trauma in the history of the patient, might have triggered the neoplastic formation from any ependymal progenitor cells in the possibly present ectopic glial tissue.

The most common subtype of extraneural ependymomas is myxopapillary ependymoma.[8] Some of the extraneural ones are cellular and present pseudopapillary structures. Our case is consistent with these reported examples. Metastatic carcinoids, metastatic carcinoma, and primitive neuroectodermal tumor should be considered as differential.

GFAP stain is helpful, as it shows positivity in the fibrillary projections of ependymoma cells.[5] EMA stain is also another diagnostic tool and intracytoplasmic spherule-like or dot-like staining is quite typical for ependymomas.[6],[9] Although our case was not positive with any of the keratin antibodies, it should be kept in mind that ependymomas may express CK7 and may be misdiagnosed as metastatic carcinoma if GFAP is not performed.[5] Due to the characteristic histopathologic appearance and immunohistochemical results such as GFAP and EMA positivity, our tumor was designated as an ependymoma.

In the 2007 edition of the World Health Organization CNS Tumors Classification, although the morphologic criteria of the classical (Grade II) and anaplastic (Grade III) ependymomas are defined,[2],[10] the criteria for grading ependymomas were not well-specified and always seem to be subjective.[2],[9] There is a growing recognition of the clinical and histopathological heterogeneity in ependymomas originating in various age groups and from different compartments of the CNS. Therefore, these may differ in clinical behavior, response to therapy and patient outcomes.[10] Parameters like cellularity, mitotic count, and Ki-67 proliferation index are used to predict the prognosis in daily practice. However, there is no clear cut-off for neither the mitotic count nor the Ki-67 proliferative index. Since our tumor showed hypercellularity, the mitotic count was counted to be 10/10 HPF and the Ki-67 staining rate was found as 10%, we graded the case as anaplastic although it might be an issue of debate.


This is the first report demonstrating a primary extraneural anaplastic ependymoma arising from the inguinal subcutaneous area. This entity should be kept in mind in the differential diagnosis of especially a metastatic carcinoma with papillary or pseudopapillary structures. GFAP staining will be a helpful diagnostic tool if the morphologic pattern is well-recognized.


The authors would like to thank Professor Dr. Sulen Sarioglu, for her help in this manuscript.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


1Ostrom QT, Gittleman H, Liao P, Rouse C, Chen Y, Dowling J, et al. CBTRUS statistical report: primary brain and central nervous system tumors diagnosed in the United States in 2007-2011. Neuro Oncol 2014;16 Suppl 4:iv1-63.
2Zawrocki A, Izycka-Swieszewska E, Papierz W, Liberski PP, Zakrzewski K, Biernat W. Analysis of the prognostic significance of selected morphological and immunohistochemical markers in ependymomas, with literature review. Folia Neuropathol 2011;49:94-102.
3Lee KJ, Min BW, Seo HJ, Cho CH. Subcutaneous sacrococcygeal myxopapillary ependymoma in Asian female: A case report. J Clin Med Res 2012;4:61-3.
4Hwang HJ, Sohn JH, Han SJ, Kim TS, Lee YS, Kim JH. Multi-disciplinary treatment of a rare pelvic cavity ependymoma. Yonsei Med J 2007;48:719-22.
5Idowu MO, Rosenblum MK, Wei XJ, Edgar MA, Soslow RA. Ependymomas of the central nervous system and adult extra-axial ependymomas are morphologically and immunohistochemically distinct – A comparative study with assessment of ovarian carcinomas for expression of glial fibrillary acidic protein. Am J Surg Pathol 2008;32:710-8.
6Mogler C, Kohlhof P, Penzel R, Grenacher L, Haag GM, Schirmacher P, et al. A primary malignant ependymoma of the abdominal cavity: a case report and review of the literature. Virchows Arch 2009;454:475-8.
7Whittemore DE, Grondahl RE, Wong K. Primary extraneural myxopapillary ependymoma of the broad ligament. Arch Pathol Lab Med 2005;129:1338-42.
8Wang Z, Huang G, Yan P, Liang R, Wang J, Yan Q, et al. Ectopic cervical anaplastic ependymoma. Pathol Int 2005;55:781-4.
99. Raghunathan A, Wani K, Armstrong TS, Vera-Bolanos E, Fouladi M, Gilbertson R, et al. Histological predictors of outcome in ependymoma are dependent on anatomic site within the central nervous system. Brain Pathol 2013;23:584-94.
10Burger PC. Tumors of ependyma and related cells. In: Burger PC, Scheithauer BW, editors. Diagnostic Pathology: Neuropathology. 1st ed. Salt Lake City: Amirys Publishing; 2012. Part 1, Section 1, p. 96-117.