Answer: Hematoma

Histology: none provided

Discussion: Composed of blood and macrophages, the mass is not the high grade glioma anticipated by the surgeon. The blood is recognizable without much effort, or overlooked as incidental, but macrophages may go undetected if the surgeon’s impression is taken at face value. A “prove-it-to-me” approach that a surgical specimen is really a neoplasm is highly recommended. Smear preparations are helpful since macrophages are readily recognized therein. Common causes of intracranial hemorrhage likely to be approached surgically include tumor such as melanoma, vascular malformation, and amyloid (congophilic) angiopathy. The last should be suspected in hemorrhages in the elderly.