Subungual squamous cell carcinoma masquerading as chronic common infection.

Subungual squamous cell carcinoma is a rare disease that has been frequently misdiagnosed as benignity due to lack of awareness among doctors. The author reports a typical case of subungual squamous cell carcinoma in a 49-year-old Thai farmer who presented with a 4-year history of chronic persistent discharging ulcer at the nail bed of the left middle finger after experiencing a minor trauma to the hyponychium. Initially, he was treated as benign infection but the condition did not improve. The nail bed was biopsied and subungual squamous cell carcinoma was finally diagnosed. One small left epitrochlear lymph node and one large left axillary lymph node were palpable. He underwent amputation of the neck of the middle phalanx of the left middle finger and biopsy of ipsilateral epitrochlear lymph node and dissection of the affected axillary tissue. The histological examination confirmed the diagnosis of subungual squamous cell carcinoma with left epitrochlear and axillary lymph node metastasis. Radiotherapy was planned.