[Infratentorial oligodendroglioma: report of a case]

Oligodendroglioma occurs primarily in the cerebral hemisphere in adult. A rare case of oligodendroglioma in the cerebellum is presented, and previous reported cases were reviewed. A thirty-one year old female was admitted to our service only with headache. CT scan demonstrated a low density mass in the vermis of the cerebellum which was not enhanced. Bilateral vertebral angiography showed an avascular mass in the vermis. The preoperative diagnosis was astrocytoma or ependymoma, and a suboccipital craniotomy was performed. The tumor which was soft, yellowish gray and well-circumscribed, was developed from the vermis and extended into the cisterna magna. The tumor which size was approximately 3 X 4 X 5 cm. Microscopically the specimen showed round, darkly stained nuclei and clear perinuclear cytoplasmic halos. Moreover, the immunoperoxidase method testified the absence of glial fibrillary acidic protein in the tumor cells. The pathological diagnosis was oligodendroglioma. Post-operatively the patient was doing well without any complications. There was no clinical nor CT evidence of tumor recurrence forty months after resection. The 11 reported cases of infratentorial oligodendroglioma including ours were analyzed and the following conclusion was obtained. Infratentorial oligodendroglioma occurs in the younger age group. The tumor has special tendency to form cyst. Frequency of calcification is low. Prognosis is good if the tumor is resected in early stage. Pre-operatively, however, it was difficult to differentiate oligodendroglioma from astrocytoma.