Subungual melanoma. Features of clinic, diagnostics and treatment

Subungual melanoma (SM) is a rare tumor and is 3-5% of all malignant skin melanoma. There was analyzed database of the Population-based Cancer Registry of the N.N.Petrov Research Institute of Oncology of St. Petersburg, the first in Russia, including information on more than 2,500 patients with malignant melanoma, of which for the period from 1986 to 2014 there were selected cases of acral lentiginous melanoma - 85 patients (3.4%). This group included 40 patients with SM (1.6%). More than half of patients were referred to a specialist in a year since the appearance of the first symptoms of the disease. Distribution of SM patients by Stages was as follows: 30% (n = 12) cases of the disease were identified in the Stage I, 40% (n = 16) - in the Stage II, 25% (n = 10) - in the Stage III and 5% (n = 2) - in the Stage IV. The most commonly misdiagnosed cases were considered as inflammation, fungal or other lesions of the nail phalanx. Histologically SM patients met all morphological types of melanoma. Over half of patients had Clark IV and V levels of invasion. The mean value of tumor by Breslow thickness was 5.5 mm. All patients with SM underwent radical surgery in the following volumes: 75% (30 cases) - amputation at the middle level (n = 16) and basic (n = 14) phalanges; 20% (8 cases) - disarticulation at the level of the proximal interphalangeal (n = 6) and metatarsusphalanx (n = 2) joints; 5% (n = 2) - resection metacarpal and metatarsal. Inguinal-femoral lymphadenectomy was performed in 8 patients with metastatic lesion of regional lymph nodes.