The patient went on to have a craniotomy. 

Histology

MICROSCOPIC DESCRIPTION: The section shows fragments of a densely hypercellular tumor and fragments of blood clot and granulation tissue containing collections of hemosiderin filled macrophages. Tumor cells have pleomorphic vesicular nuclei many with conspicuous nucleoli and a variable amount of pale cytoplasm. Finely granular black-brown pigment is noted within the cytoplasm of many tumor cells. There are frequent mitotic figures and foci of tumor necrosis are also noted. Tumor cells show strong immunostaining for tyrosinase. The features are of metastatic malignant melanoma.

FINAL DIAGNOSIS: Metastatic malignant melanoma.