Recurrent subependymoma of fourth ventricle with unusual atypical histological features: A case report

Document Type

Article

Abstract

Subependymoma is a rare subtype of benign ependymal neoplasm with distinct histological features. Anaplastic transformation has not yet been reported in this tumor to date. We present here a very unusual case of a 62-year-old woman with recurrent subependymoma of the fourth ventricle with multiple atypical histological features. Histologically, the resected recurrent tumor showed characteristic small cell clusters and nests of ependymal cells with an interspersed gliofibrillary matrix as seen in a classic subependymoma. In addition, there were very unusual histological features, including multiple areas of necrosis, microvascular proliferation, thrombosed blood vessels, and scattered mitotic figures. No coexisting ependymoma component of higher World Health Organization (WHO) grade was present. Immunohistochemically, MIB-1 labeling index was high, with up to 15% in the highest areas. Review of this patient's initial tumor, which was resected 6 years prior to recurrence, demonstrated features of a typical classic subependymoma without atypical features or a secondary tumor component. Subependymomas are known to be low-grade tumors and are usually cured if completely excised. The tumor presented here is unique in that several atypical pathological features were found in an otherwise typical subependymoma. Our case may represent anaplastic transformation of subependymoma, although no such examples have been reported to date.

Medical Subject Headings

Cerebral Ventricle Neoplasms (pathology); Female; Fourth Ventricle (pathology); Glioma, Subependymal (pathology); Humans; Magnetic Resonance Imaging; Middle Aged; Neoplasm Recurrence, Local (pathology)

Publication Date

8-1-2015

Publication Title

Pathology international

E-ISSN

1440-1827

Volume

65

Issue

8

First Page

438

Last Page

42

PubMed ID

26059172

Digital Object Identifier (DOI)

10.1111/pin.12316

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