A diagnostic pitfall: Angiosarcoma of the brain mimicking cavernous angioma.

Primary or secondary angiosarcoma in the central nervous system is rarely reported. We present a rare case of cerebral angiosarcoma, which comprised both poorly-differentiated solid areas and well-differentiated areas that led to the misdiagnosis of cavernous angioma. A 79-year old woman presented with an intracerebral hematoma in the left frontal lobe that was misdiagnosed as a hemorrhage from a cavernous angioma at initial operation. At a second surgery, the lesion was diagnosed as angiosarcoma involving the cerebellum, heart, femur, sacro-iliac bones and other locations. An autopsy suggested that the angiosarcoma of the heart was the primary lesion, which was occult at the time of the initial operation. Angiosarcoma may have areas with different degrees of differentiation and when a cavernous angioma is suspected histopathologically, the specimen should also be carefully explored for poorly-differentiated areas and the diagnosis of primary or secondary angiosarcoma considered.