Giant Cell Ependymoma of the Filum Terminale

Abstract

We describe two histologically unusual cases of ependymoma of the filum terminale. Both tumors occurred in 14-year-old boys. An intradural encapsulated mass attached to the filum terminale was demonstrated radiologically in both cases and totally resected at surgery. In case 1 the neoplasm was uniformly composed of pleomorphic giant cells and was without perivascular pseudorosettes or myxopapillary changes. Case 2 was a myxopapillary ependymoma with multiple foci of pleomorphic giant cells. Neither tumor had prominent mitotic activity, necrosis, or endothelial proliferation. Both tumors were immunopositive for cytokeratin and glial fibrillary acidic protein. Ultrastructural features included basal laminae, interdigitating cell processes, microvilli, cilia, intercellular junctions, and cytoplasmic intermediate filaments. Cytogenetic analysis in case 1 showed a hypodiploid karyotype with monosomy of chromosomes 1, 10, 14, 16, 20, and 22. We interpret both tumors as most consistent with a variant of ependymoma. Because of the unique gigantocellular light microscopic appearance of the entire tumor in case 1, we propose classifying this tumor as a new morphologic subtype: giant cell ependymoma of the filum terminale. The combination of gigantocellular and myxopapillary features in case 2 supports a histogenetic relationship between giant cell ependymoma and myxopapillary ependymoma.

Ependimomas del filum terminal. Análisis de 20 casos consecutivos

“…Estudios recientes han podido observar un alto índice de expresión de la prostaglandina COX-2 y del factor de crecimiento endotelial (VEGF) en los ependimomas espinales y con mayor incidencia en los de estirpe mixopapilar 24 ; de confirmarse en posteriores estudios esta expresión, podría dar lugar en el futuro a una nueva modalidad de tratamiento mediante inhibidores específicos de la angiogénesis tumoral 23 . En la literatura se han descrito otras variedades histológicas de ependimomas del filum como subependimomas, ependimomas celulares, de células gigantes 50 , tanacíticos 40 o ependimomas grado II 20 .…”

Giant cell ependymoma of the cervical spinal cord: case report and review of the literature

“…To date eight cases of GCE have been documented in the literature [1,3,6,7,10,14,15,19]; only one of these was located in the spinal cord [7]. Our case is the second example of a cervical spinal cord GCE, and the first with focal calcifications.…”

“…Zec et al [19] first described two cases of giant-cell ependymoma of the filum terminale in 1996. They suggested that the absence of perivascular pseudorosettes in GCE might reflect the failure of the neoplastic cells in this tumour to elaborate perivascular processes.…”

“…GCE has a good prognosis [19] because, as well as in subependymal giant cell astrocytoma [4] and pleomorphic xanthoastrocytoma [11], the presence of pleomorphic giant cells has no correlation with an aggressive behaviour. These histopathological features correlate with the clinical outcome in the present case: at 18-month follow-up progressive neurological improvement has been registered and no signs of tumour recurrence are shown on MRI scan, despite no adjuvant therapy, i.e.…”

“…Giant cell ependymoma (GCE) is a rare subtype, first described in 1996 [19], characterized histologically by the presence of pleomorphic giant cells and clinically by a favourable prognosis. Differential diagnosis of GCE includes anaplastic oligodendroglioma, subependymal giant cell astrocytoma, pleomorphic xanthoastrocytoma and giant cell glioblastoma [1].…”