Combined tumors of malignant melanoma (MM) and squamous cell carcinoma (SCC) are extremely rare and have unknown biological potential. Different theories of their development, including collision and dual/divergent differentiation, are proposed. Although some observations suggest an indolent course for such tumors, a case of MM metastasis was reported in a patient who initially presented with a combined MM-SCC tumor. Re-excisions of such tumors may show MM in situ and should be treated accordingly. Herein we present another case of a combined MM-SCC tumor in a 78 male patient with lentigo maligna seen after complete re-excision of the tumor.
Keywords: Melanoma; skin neoplasms; squamous cell carcinoma.