Keratoacanthoma or verrucous carcinoma? A case report.

A 75-year-old woman presented with a slow growing lesion on the plantar surface of her right foot, which had changed in appearance over several months. The patient underwent excision of the suspicious lesion, and a provisional diagnosis of keratoacanthoma was given. However, approximately three months later, the lesion grew to its original size. Subsequent re-evaluation and consultation resulted in changing of the diagnosis to verrucous squamous cell carcinoma. The patient underwent a wider excision with split thickness skin grafting. The authors discuss this rare pedal entity and the inherent difficulty in both its clinical and microscopic differentiation.