Epidermotropic Metastatic Malignant Melanoma / 대한피부과학회지

Cutaneous metastases of malignant melanoma are usually confined to the dermis or subcutaneous fat. In some instances, however, they may involve the epidermis. A 68-year-old woman with a malignant melanoma on the subungual area of the right great toe presented with multiple blackish pinhead-sized macules surrounding an ulcerative lesion on the right great toe. Histopathological study of the macules showed atypical melanocytes and melanocytic nests in the papillary dermis and the dermoepidermal junction. A thinning of the epidermis, widening of the dermal papillae by aggregated atypical melanocytes, epidermal collarette formation, and angiotropism were also seen. A diagnosis of epidermotropic metastatic malignant melanoma (EMMM) was made. EMMM is a specific form of metastatic malignant melanoma that is associated with epidermotropism of melanoma cells and several histopathological features. The differential diagnosis between primary malignant melanoma and EMMM can be difficult because of their similar clinical and histological features. Here, we report a case demonstrating EMMM.

Epidermotropic Metastatic Melanoma Clinically Resembling Agminated Spitz Nevi

Herein, we report a 36-year-old Asian male patient who presented with grouped multiple erythematous waxy papules and nodules on his right medial thigh. He had undergone amputation of the right second toe because of a stage IIa malignant melanoma, 3 years previously. At the time of surgery for the primary tumor, right inguinal lymph node dissection revealed no nodal involvement. Three years after the diagnosis of the primary tumor, crops of multiple erythematous papules and nodules developed. Initial histopathologic evaluation of the papules showed nests of small epithelioid cells similar to compound nevi. However, cytologic features, including high mitotic figures, lack of maturation, and some hyperchromatic nuclei suggested metastatic melanoma. In addition to the pathologic findings, the tumors were on the right thigh, which was the same side as the primary malignant melanoma. The patient underwent wide excision of the tumor and split-thickness skin grafting.