The patient had a history of melanoma and went on to have a craniotomy. 

Histology

MICROSCOPIC DESCRIPTION:

Paraffin sections show fragments of unremarkable cerebellar cortex and a separate large fragment which is largely necrotic and shows recent hemorrhage. Within this fragment there are scattereed aggregates of atypical cells which have irregularly shaped vesicular nuclei with prominent nucleoli and a small amount of pale cytoplasm.

These show immunostaining for tyrosinase and melan A. No staining in these cells for cytokeratins AE1/AE3 or CAM5.2 is seen. The features are strongly suggestive of metastatic malignant melanoma.

DIAGNOSIS:

Metastatic malignant melanoma.