An uncommon malignant cutaneous squamomelanocytic tumor.

The intermingling of two malignant neoplasms within the same cutaneous tumor is rare. No consensus has been reached for a clear definition and categorization. In the current study, we describe a cutaneous neoplasm; a squamomelanocytic tumor (SMT) with histological features combining those of a squamous cell carcinoma (SCC) and a malignant melanoma (MM). This is the second report of an oculocutaneous SMT, and concerns a subject with a 20-year history of solar lentigo coexisting with solar keratosis in the primary lesion. This type of tumor is quite rare, with a distinct cytological architecture and immunohistochemical features, and the differential diagnosis of SMT may be considered. However, the histogenesis, biological behavior and malignant potential of SMTs remain a matter of speculation. With regard to the treatment, complete surgical resection and close follow-up are recommended.