Leptomeningeal dissemination of a pediatric neoplasm with 1p19q deletion showing mixed immunohistochemical features of an oligodendroglioma and neurocytoma.

Leptomeningeal dissemination of an oligodendroglioma is rarely reported in the neurosurgical literature, especially in cases with a classical 1p19q deletion. The authors describe a case wherein a 1p19q deletion in a disseminated tumor with mixed immunohistochemical features of oligodendroglioma and neurocytoma was encountered and treated. Stereotactic right frontal craniotomy was undertaken for obtaining definitive histological diagnosis. The results revealed a neuroectodermal neoplasm with histologic and immunohistochemical features of oligodendroglioma and neurocytoma. FISH analysis confirmed classical 1p19q deletion. The patient was treated postoperatively with chemotherapy and radiation therapy. He showed good clinical response and remains alive 16 months after diagnosis.