Periungual Bowen Disease Mimicking a Melanocytic Nevus: A Case Report.

Periungual Bowen disease is an uncommon form of squamous cell carcinoma in situ that may mimic benign pigmented lesions, such as melanocytic nevi. We report a case of a 36-year-old man who presented with an irregularly shaped brown macule on the periungual area of the right third finger, with a history of gradual enlargement over 8 years. The patient reported occasional periungual trauma because of nail picking but had no significant medical history. A punch biopsy was performed, and histopathological examination confirmed the diagnosis of Bowen disease. The lesion was completely excised, and no recurrence was observed during follow-up. This case highlights the importance of clinical suspicion and histological evaluation for chronic pigmented periungual lesions that may resemble benign conditions.