The patient went on to have surgery. 

Histology

Paraffin sections show fragments of a densely hypercellular tumor. Tumor cells have markedly pleomorphic round and oval nuclei with vesicular chromatin, prominent nucleoli and a variable amount of eosinophilic cytoplasm. The cytoplasm of scattered cells contains finely granular black-brown pigment. Frequent mitotic figures are identified and there is extensive tumor necrosis. Tumor cells show positive immunostaining for tyrosinase.  

FINAL DIAGNOSIS: Metastatic malignant melanoma.