[A case of an cerebello-pontine angle pineoblastoma].

An extremely rare case of a left cerebello-pontine angle (CP angle) pineoblastoma has been reported. The patient was a 32-year-old male whose initial manifestations were those of increased intracranial pressure. CT scan showed a large enhancing mass located at the left CP angle, associated with a moderate occlusive hydrocephalus. Left suboccipital craniectomy was performed. The mass was an extramedullary tumor which had compressed the left cerebellar hemisphere, and was easily separable from the adjacent tissue. The tumor was totally resected, and the patient had a temporary release from the symptoms. Recurrence and spinal dissemination were found within the ensuing few months. The tumor had invaded deeply through the left CP angle into the cerebellar parenchyme, and showed no anatomical connection with the pineal body. The tumor dissemination was also observed widely in the spinal subarachnoid space. No abnormalities at the pineal region were able to be confirmed using CT and MRI studies. Irradiation to the whole brain, to the localized left CP angle and to the spinal cord with additional chemotherapy was given. The patient died half a year after the first operation. Autopsy was not performed. Histopathologically, the tumor was delineated into lobular structures by reticulin fibrils and vimentin-positive interstitial tissue. Tumor cells were small in size, and had irregularly shaped hyperchromatic nuclei with increased mitotic figures, and formed various types of rosettes; pineocytomatous, Flexner-Wintersteiner, Homer-Wright and perivascular. Fine argyrophilic cell processes with club-shaped expansions were demonstrated inside the pineocytomatous rosettes.(ABSTRACT TRUNCATED AT 250 WORDS)