Squamous Cell Carcinoma of the Nail Unit: A Case Report

We report an 83-year-old woman who presented to her primary care provider with pain and swelling of her left thumb distal phalanx for 1 week. Initial imaging was benign. The patient underwent treatment for presumed soft tissue infection with 2 separate oral antibiotic courses. An intralesional corticosteroid injection did not provide relief and repeat radiographs showed a destructive lesion to the tuft of the distal phalanx. Advanced imaging showed bony destruction and biopsy revealed invasive squamous cell carcinoma involving the nail plate with bony invasion. Amputation through the interphalangeal joint of the left thumb was conducted with disease-free margins. The patient currently is following with oncology for clinical surveillance. Given this entity's rarity, either persistent or recurrent nail unit disease must be investigated thoroughly with early referral to a surgical hand specialist as appropriate.