Eruptive melanocytic nevi heralding the diagnosis of metastatic malignant melanoma: A case report

EMN: eruptive melanocytic nevi EMMM: epidermotropic metastatic malignant melanoma ITM: in-transit metastases INTRODUCTION Eruptive melanocytic nevi (EMN) are an unusual phenomenon characterized by the rapid appearance of multiple melanocytic nevi. Whether atypical or benign, EMN are associated with various medications and diseases but not previously with melanoma. EMN have been described in internal malignancy, such as prostate cancer, in which it is proposed as a paraneoplastic phenomenon, although the mechanism is unclear. One cutaneous phenomenon that arises from primary melanoma is epidermotropic metastatic malignant melanoma (EMMM), whereby malignant cells migrate from the dermal metastasis into the epidermis. Epidermotropic metastases are metachronous with the primary tumor or appear after resection or treatment of the primary disease, and melanoma is no exception. Eruptive nevi may be clinically mistaken as EMMM; therefore, making the distinction is important. We report a case of a patient who had 2 concurrent primary melanomas treated with wide local resection and in whom EMN developed, with no signs of EMMM, 8 weeks before diagnosis of widespread metastatic melanoma.