Superficially-located oligodendroglioma associated with intratumoral and peritumoral cysts--case report.

A 72-year-old male presented with a superficially-located oligodendroglioma associated with intratumoral and peritumoral cysts. Neuroimaging showed the outer cyst wall as enhanced but not the inner cyst wall. The outer cyst was removed and a biopsy taken of the solid component. The inner cyst wall appeared to consist of non-neoplastic tissue. Histological examination showed the tumor was an oligodendroglioma with tumor cells in the outer wall. The outer cyst was probably the result of blood-brain barrier disruption and intratumoral hemorrhage. The inner cyst probably resulted from reactive gliosis or peritumoral edema. Cyst formation in intraaxial tumors occurs through similar mechanisms to those of extraaxial tumors.