[Case of acoustic neurinoma with intratumoral hemorrhage extending to cerebellar hemisphere].

A case of acoustic neurinoma which developed intratumoral hemorrhage extending to the right cerebellar hemisphere, is reported. A 54-year-old man was diagnosed as cerebello-pontine angle tumor, possibly acoustic neurinoma, from typical clinical course, neurological signs and findings of skull X-P and CT scan at the first visit to our out-patient clinic on July 28, 1981. On August 6, 1981, he was transferred to our in-patient ward in emergency because of sudden onset of headache and impairment of consciousness. At emergency admission, he was found to be comatous and CT scan revealed round-shaped high density in the right cerebellar hemisphere, continuing from the right cerebello-pontine angle tumor with enlarged lateral ventricles, which indicated occurrence of intratumoral hemorrhage. At emergency operation, hematoma in the right cerebellar hemisphere was evacuated and the tumor in the right cerebello-pontine angle was partially resected. Microscopically, the tumor was composed of compact, finely fibrillated cells of Antoni A tissues, and loose patterns of Antoni B tissue, being diagnosed as schwannoma, and also abnormal vascular proliferations were identified just adjacent to foci of hemorrhage noted within tumor tissues. The pattern of abnormal vascular proliferations within this tumor were almost identical with telangiectasia. The authors concluded that intratumoral hemorrhage in this case occurred most likely due to disruption of histologically verified abnormal vascular proliferations.