A 36-year-old Korean woman visited our clinic because of a lesion on her right index finger that had been slowly growing over a period of 6 months. On physical examination, 2.5 x 1.5 cm sized erythe- matous plaque with an incomplete hyperkeratotic surface and partial nail plate loss were observed (Fig. 1). Due to suspicion of Bowen’s disease, lichen planus, sarcoidosis, deep mycosis, and others, a punch biopsy was performed. The subsequent histo- logic examination showed atypical nevoid cell nests which occupied the papillary and reticular dermis. Immunohistochemical staining showed positive re-activity for S-100 protein and HMB-45. There was no sentinel lymph node involvement. Under a diagnosis of amelanotic melanoma of Breslow thickness 2 mm and Clark level IV, she was transferred to our plastic surgery department, where her index finger was amputated below the proximal interpharyngeal joint. A histologic section of the amputated finger showed atypical melanocytic proliferation at the nail matrix dermoepidermal junction.
Fig. 1. Asymptomatic, erythematous plaque with dystrophic and partial loss of the nail plate of the index finger.
These findings demonstrated that the primary melanoma lesion was located in the nail matrix and that the lesion had spread distally to the nail bed, and proximally to the ventral proximal nail fold, the dorsal proximal nail fold, and to adjacent skin. The tumor cells were ovoid to irregular in shape with slightly hyperchromatic nuclei and moderate cytolo- gic atypia (Fig. 2A). In histologic sections from the nail fold and neighboring finger skin, the tumor was found to be composed of nests with crowded irregular epithelioid cells separated by fibrous septa (Fig. 2B). Immunohistochemical staining for Melan- A showed positive reactivity in melanoma cell cytoplasms (Fig. 2C). Further laboratory examinations, CT and PET CT findings were unremarkable and showed no evidence of metastasis. Her final diagnosis was of amelanotic subungual melanoma, stage Ib. cialis super active
Fig. 2. (A) Histologic findings of the amputated finger showing melanoma cells and cell nests involving the dermoepidermal junction of the nail matrix and extending to the nail bed (H&E, x 25, Inset: H&E, x 100). (B) Histologic section from the periungual lesion showing tumor cell nests packing the upper two thirds of dermis (H&E, x 40). (C) Immunohistochemical staining for Melan-A showing positive cytoplasmic reactivity in melanoma cells (Melan-A stain, x 100).