Desmoplastic infantile ganglioglioma with extraparenchymatous cyst--case report.

A large supratentorial tumor associated with an extraparenchymatous cyst and multiloculated intraparenchymatous cysts occurred in a 14-month-old infant. This case had all the characteristic features of desmoplastic infantile ganglioglioma both clinically and histologically. The notable difference was the extraparenchymatous cyst. The extraparenchymatous cyst was probably caused by entrapment of cerebrospinal fluid in the subarachnoid space by some check-valve mechanism because the leptomeninges were commonly involved in the tumor. A similar mechanism may explain the etiology of the intraparenchymatous, disproportionately large cyst in desmoplastic infantile gangliogliomas.