Epidermotropic Metastatic Malignant Melanoma / 대한피부과학회지

ABSTRACT

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.