Congenital gliosarcoma: detailed clinicopathologic documentation of a rare neoplasm.

Congenital brain tumors are rare. Clinically, they often result in macrocrania, hydrocephalus, and focal neurologic deficits. Fetal onset may result in dystocia and stillbirth. Antenatal detection is becoming more common as the result of neuroimaging, and modalities such as magnetic resonance imaging can assist in narrowing the pathologic differential diagnoses. Teratomas and astrocytomas appear to be the most common congenital neoplasms. Amongst the latter, all grades and many subtypes are represented in the congenital time period, including the diffusely infiltrative forms of astrocytoma. Gliosarcoma is currently considered a variant of glioblastoma (i.e., astrocytoma, World Health Organization grade IV) that exhibits genetically similar yet phenotypically separate histologic regions of high-grade astrocytoma and sarcoma. Only rare instances of congenital gliosarcoma have been reported. We detail the case of a 1-day-old term male who presented with macrocrania, hydrocephalus, and signs of increased intracranial pressure. Pathology revealed evidence of a classic gliosarcoma.