PEComas can be differentiated from malignant melanoma based on a negative history for melanoma, visceral location of tumor, perivascular accentuation of tumor cells, immunoreactivity for myoid markers (i.e., smooth muscle actin, muscle-specific actin, and desmin), and absence of the t(12:22) translocation [2]. The gene discussed is DES; the disease is neoplasm with perivascular epithelioid cell differentiation.