PECs are hybrid tumor cells characterized by immunoreactivity for both melanocytic and smooth muscle markers, such as HMB45, HMSA-1, MelanA/Mart1, microphthalmia transcription factor (Mitf), actin, and, less commonly, desmin; the immunoreactivity for vimentin is usually inconspicuous [3–5]. The gene discussed is DES; the disease is neoplasm.