Metastasis to hypopharynx from epidermotropic metastatic malignant melanoma.

Previous reports proposed the concept and criteria of epidermotropic metastatic malignant melanoma (EMMM): (a) dermal involvement equal to or broader than the epidermal involvement, (b) atypical melanocytes within the dermis, (c) thinning of the epidermis, (d) widening of the papillary dermis with an epithelial collarette, and (e) vascular invasion of atypical melanocytes. However, it remains unclear whether EMMM also involves the mucosal epithelium. In this case, the patient was diagnosed with EMMM based on the histopathological findings of the patient's multiple skin lesions and clinical course. The patient also developed metastasis to the hypopharynx. Although histopathological findings of the lesion suggested the possibility of melanoma in situ, as the lesion included atypical melanocytes in the mucosal epithelium, the clinical course supported the diagnosis of hypopharyngeal metastasis from EMMM. This case suggests that EMMM may have epitheliotropic features not only in the skin but also in the mucosa.