Tumors composed of malignant epithelial and melanocytic populations: a case series and review of the literature.

Over the last 30 years, there have been approximately 49 case reports of tumors composed of both malignant epithelial and malignant melanocytic populations. Herein, we present four additional cases of combined tumors that consist of two phenotypically distinct but intermingled populations of malignant cells. Each tumor was composed of an invasive melanoma closely associated with either a basal cell carcinoma or a squamous cell carcinoma. We review all previous case reports in the English literature and attempt to clarify the terminology and summarize what is currently known about these unique tumors.