A Case of Onycholemmal Carcinoma in a 77-Year-Old Man

A 77-year-old man with a history of stage IV non-small cell lung cancer presented with a slow-growing, painful mass on his left second finger, diagnosed as onycholemmal carcinoma, a rare malignant tumor originating from the nail bed epithelium. The tumor was characterized by atypical keratinocytes and keratin-filled cysts, with no regional lymph node metastasis or systemic spread. Despite surgical amputation of the affected phalanx, the patient died 4 months later due to progression of his lung cancer. Onycholemmal carcinoma is often misdiagnosed due to its indolent nature and atypical presentation, necessitating careful examination and biopsy for accurate diagnosis. Treatment typically involves surgical removal, though less aggressive treatments have shown comparable effectiveness.