Giant cell ependymoma: A case report

Abstract

Ependymomas account for 3–9% of all neuroepithelial tumors. A peculiar variant of ependymoma known as “giant cell ependymoma” (“GCE”) is especially rarely reported, it may pose some difficulties for the diagnosing neuropathologist. Here we present a case of a giant cell ependymoma occuring in a 17-year-old patient with the history of 2-year recurrent headaches and a 1-month history of vision impairment. CT scanning demonstrated a mass in the left occipital lobe, arising from the occipital horn of the lateral ventricle. Histological, immunohistochemical and electron microscopic findings were consistent with high-grade ependymoma. Especially striking was the presence of bizzare pleomorphic giant cells which predominated in the tumor tissue. As a result the diagnosis of GCE was established. This type of neoplasm necessitates, at least in theory, differentiation with anaplastic oligodendroglioma, clear cell ependymoma, pleomorphic xanthoastrocytoma, giant cell glioblastoma, and subependymal giant cell astrocytoma. To date giant cell ependymomas (GCEs) were reported in seven cases in the literature. To the best of our knowledge this is the 8th case in the literature. In spite of apparently “worrisome” histology GCE seems to be a neoplasm with a relatively good prognosis.

Introduction

GCE is a particularly rare variant of ependymoma. To the best of our knowledge, to date, only seven cases of GCE have been described in the literature [1]. The cases reported so far are summarized in Table 1. Because of such a low number of the reported cases it is impossible to draw definite conclusions as for the biological and clinical behavior of the tumor (see Section 4).

Ependymomas are neuroepithelial neoplasms occurring mainly in childhood and in young adults. The ventricular system and its vicinity is a typical site of these slow-growing tumors however they appear along the whole neuroaxis including the spinal cord and also extraventricularly: the latter probably originating from embryonic ependymal remnants. There is a poor association between the biological behavior and morphological presentation of the tumor, in consequence, it is difficult to predict the patient's outcome on the grounds of histopathological examination. Age is a well-known factor, with the tumors affecting children being more aggressive. Apart from “standard” ependymomas the WHO classification incorporates some particular variants, such as cellular, papillary, clear cell and tanycytic ependymoma [2]. Other variants, as ependymoma with lipomatous differentiation, signet ring cell ependymoma, melanotic ependymoma and giant cell ependymoma, are extremely rare.

The majority of the reported cases of GCE (see Table 1) were seen in young people. Three tumors were localized in the vertebral canal and five intracranially (that number includes the present case). In the present paper, the authors report a case of GCE arising from the lateral ventricle in 17-year-old subject.