A Subungual Nevoid Melanoma of the Right Hallux from a 65-Year-Old Man: A Case Report.

Nevoid melanoma (NeM) is a rare variant of malignant melanoma characterized by slight cellular atypia, polymorphism, and incomplete maturation. It most frequently occurs on the trunk and arms but rarely on the foot. Here, we report a subungual NeM of the right hallux. A 65-year-old man presented with severe pain of 6 months' duration to his right great toe following self-treatment for an ingrown nail. He was evaluated and treated with debridement of the toenail at an urgent medical center 3 months prior. However, this had not relieved his pain. The patient also noticed discoloration of his distal great toe over the past 3 months. Removal of part of the ingrown nail revealed a pigmented mass extending distally from the matrix. Surgical excision of the mass was performed because of the concern for malignancy. The diagnosis of NeM was based on histologic analysis along with enhanced diagnostic modalities. The patient was further treated with surgical amputation of the great toe and anti-programmed cell death-1 therapy. The patient had no relapse at 1-year follow-up. Nevoid melanoma is a rare variant of malignant melanoma on the toes, which needs to be differentiated from a nevus with atypia, with a variety of modalities including cellular and molecular profiling. The optimal treatment is amputation.