Perforating metastatic melanoma

A 70 year-old man was diagnosed with a nodular type malignant melanoma involving the lower back with satellite lesions (stage IIIB, T4b N2c M0, Breslow’s tumor thickness; 10.3 mm, Clark’s level; IV) (Fig. 1a). Sentinel lymph node evaluation was not performed. Three months after the excision of the primary melanoma with a 2-cm margin, skin metastasis appeared on his right inguinal region. Physical examination an additional month later revealed a firm, black-colored 5-mm sized nodule with crusts on the surface on the right thigh, with surrounding subcutaneous induration (Fig. 1b). Dermatoscopic examination found that keratins at the surface of the central lesion and a bluewhite veil at the periphery. Histological examination of a totally removed nodule showed a small, symmetric and well-circumscribed lesion composed of nests of numerous atypical melanocytes in the dermis (Fig. 1c). Those atypical cells were positively stained with Melan-A, HMB45 and S-100. Tumor cells were located in abutment with and also within the epidermis. Nests of atypical melanocytes were confined to the crusts and perforated the skin surface (Fig. 1d). Treatment with chemotherapy was not implemented because the patient refused aggressive treatments. Six months after the onset of skin metastasis, he died of respiratory failure.