Report of a case of giant cell ependymoma with unusual clinical and pathological presentation.

Giant cell ependymoma (GCE) is a very uncommon variant of ependymoma, known for having varying degrees of nuclear pleomorphism. There are only 34 reported cases of GCE in the English literature. We describe an additional case of a young woman who presented with a tumor located in sacral soft tissue, which was not connected to the spinal cord and did not show additional lesions in the central nervous system. Complete tumor resection was performed and no recurrences or metastasis were detected after 5 months of follow-up. Only one of all the reported GCE was located in the sacral subcutaneous region, where ependymomas are rarely found and usually have myxopapillary histology. Ours is the second report showing microscopic features of GCE in the soft-tissue region. GCE should be considered in the differential diagnosis of lumbosacral subcutaneous tumors to avoid misdiagnosing it as a malignant lesion. Since GCE could be an extraspinal extension of an intraneural ependymoma, it would be important to evaluate whether it is connected to the spinal cord.

Immunohistochemical Expression of Progesterone Receptors in Nonmeningothelial Central Nervous System Tumors.

INTRODUCTION: Immunostaining of progesterone receptors (PRs) has been described as a prognostic factor related to recurrences in meningiomas. However, its expression in other primary intracranial tumors has been poorly studied. In this paper, we compare the pattern of expression of the receptor in meningiomas with that of nonmeningothelial intracranial tumors to evaluate its value in the diagnosis of the former. MATERIALS AND METHODS: A total of 42 nonmeningothelial intracranial tumors (21 glioblastomas, 4 anaplastic oligodendrogliomas, 4 oligodendrogliomas, 1 pilomyxoid astrocytoma, 3 ependymomas, 8 schwannomas, 1 chordoid chordoma) and 32 meningiomas (1 rhabdoid, 1 papillary, 5 atypical, 7 with histologic features of more aggressive behavior, 1 microcyst, 8 meningothelial, 7 transitional, 2 fibroblastic) were studied for PR by immunohistochemistry. RESULTS: About 73.8% of the nonmeningothelial tumors and 100% of the meningiomas were positive for the receptor, the difference being statistically significant (P=0.0017). The mean percentage of positive tumor cells per high-power field was frequently higher than 30% in meningiomas and lower than 10% in nonmeningothelial tumors (P=0.0001). CONCLUSIONS: Although we detected that immunostaining for the PR is more frequently observed in meningiomas, we confirmed its expression in diverse nonmeningothelial primary intracranial tumors. Immunohistochemistry for PR would be useful in the diagnosis of meningioma only when its positivity shows a mean higher than 30% of the positive tumor cells per high-power field.