Unique desmoplastic cerebral tumor in a patient with complex partial seizures

Primary brain tumors with prominent desmoplasia include the gliofibroma, desmoplastic infantile ganglioglioma (DIG), pleomorphic xanthoastrocytoma (PXA), and desmoplastic cerebral astrocytoma. In the present report, we describe unusual pathological appearances in two successive resections of a left temporal tumor in a patient with complex partial seizures. Both tumors showed focal astroglial and very prominent neuronal differentiation. In the first resection at age 11 years, the tumor showed only focal desmoplastic areas and prominent neuronal differentiation with bizarre atypical giant cells. In the second resection at age 14 years, the morphology was dramatically different. Now the tumor showed marked desmoplasia with tumor cells coexpressing neuronal and glial markers. Electron microscopy showed prominent neuronal differentiation in both resections and presence of basal lamina around tumor cells. Our case represents a unique example of an extraordinary degree of neuronal differentiation in a desmoplastic cerebral tumor. While cellular pleomorphism in a desmoplastic tumor traditionally suggests the diagnosis of PXA, we wish to underscore that many cells exhibiting marked cytologic atypia may in fact be of neuronal rather than of glial origin as in our case.