Pituitary apoplexy, characterized by sudden onset or acute progression of signs and symptoms of pituitary adenoma, is rare yet well-known. One such case is presented with clinical course, neuroradiological findings and autopsy. A 53-year-old female complained of sudden onset of severe headache, and rapidly deteriorated in the level of consciousness. Five days later, she became comatose and was admitted to National Sendai Hospital. Plain skull films and carotid angiograms revealed a remarkably large mass in the pituitary fossa. Death came ten hours after admission. Autopsy revealed a giant tumor (10 X 5 X 7.5 cm) destroying the sella turcica and protruding toward both the nasopharyngeal cavity and the hypothalamic region. Microscopically, diagnosis was made as chromophobe adenoma with fresh hemorrhage in the tumor.