Chordoid glioma of the third ventricle: Confirmatory report of a new entity

The term "chordoid glioma" was recently introduced to denote a circumscribe d, apparently low-grade neoplasm arising in or preferentially involving the third ventricle of middle-aged women, We report biopsy and postmortem find ings in a 60-year-old woman with symptoms of forgetfulness, headache, and l ethargy. Neuroimaging showed a contrast-enhancing third ventricular mass wi th obstructive hydrocephalus, The tumor was subtotally resected. Microscopi cally, it consisted of dusters and strands of epithelioid cells in a mucoid matrix. Its margins were remarkably discrete and showed little tendency to infiltrate surrounding brain parenchyma. The majority of neoplastic cells were glial fibrillary acidic protein (GFAP) and vimentin positive, whereas S100 protein labeled only individual cells. Stains for epithelial membrane antigen (EMA) and cytokeratin were nonreactive. There was no evidence of ne uroendocrine differentiation or expression of estrogen and progesteron rece ptors, Lymphoplasmacellular infiltrates were noted throughout the lesion an d at the tumorbrain interface, The MIB-1 labeling index averaged 1.5%, At p resent, chordoid glioma is considered a glial neoplasm of uncertain histoge nesis with distinct clinicopathologic features. Copyright (C) 1999 by W.B. Saunders Company.