Abstract
We report two patients with subungual melanoma (SUM) that developed after traumatic onycholysis. Case 1: A 61-year-old man had SUM Stage II (pT3N0M0) on his left index finger, which he had struck twice with a hammer 10 years ago. Half of his nail was removed at that time and the wound had been repeatedly infected since then. A granulomatous nodule was present on his left index finger. Histology of the nodule showed malignant melanoma with a tumor thickness of 2.0mm. Case 2: A 58-year-old woman had SUM Stage III B (pT4N1M0) on her right thumb. She had injured the nail of her right thumb with a thick staple in a corrugated cardboard box soon after burning the thumb one year ago. The nail was completely removed, and a gray-colored nodule later developed on it. Histological examination showed malignant melanoma with a tumor thickness of 5.0mm. She had already experienced axillar lymph node metastasis. Previous reports of 14 cases and our cases indicate that severe trauma with destruction or deformity of a nail tends to cause invasive melanoma, greater than pT2. It should be noted that six of sixteen cases had melanomas after repeated trauma on the nail.
