Pediatric chordoid glioma with chondroid metaplasia.

Chordoid gliomas are uncommon primary brain tumors that arise in the region of the third ventricle. Reports of this entity to date have been limited to adults. We present a case of a chordoid glioma arising in the hypothalamic/third ventricle region of a 12-year-old male who presented with visual symptoms. The neoplasm consisted of cords and clusters of well-differentiated, spindled-to-rounded cells containing abundant eosinophilic cytoplasm within a prominent mucinous matrix. Unlike other chordoid gliomas, this lesion contained islands and sheets showing cartilaginous differentiation intermixed with the glial component. A graded transition between neoplastic glial and chondroid regions was evident, and cells in both regions were strongly immunoreactive for GFAP and S-100. Cartilaginous metaplasia is infrequent in gliomas, but occurs most often in pediatric neoplasms of the midline such as this chordoid glioma. Thus, chondroid metaplasia represents an unusual histopathologic feature of chordoid glioma-in this case, presenting in a child.