Acute Cerebellar Infarction Presenting as a Posterior Fossa Mass

Thirteen cases of acute cerebellar infarction presenting clinically as a posterior fossa mass with compression of the brainstem are reported. Carotid angiograms in 5 of 8 cases showed retrograde filling of the basilar artery via the posterior communicating artery and retention of contrast agent in the basilar artery for several seconds. In the 3 pneumoencephalograms obtained, there was sufficient filling of the fourth ventricle with air to permit localization of the posterior fossa mass. Obstructive hydrocephalus and cerebellar tonsillar herniation, frequent effects of the cerebellar mass, were demonstrated both by angiographic and encephalographic studies. The clinical situation is an emergency and may be fatal unless prompt surgical decompression can be carried out.