Are keratoacanthomas really squamous cell carcinomas?

Controversy continues to exist as to whether or not a keratoacanthoma is a benign lesion and can be accurately differentiated from a squamous cell carcinoma. From a review of the available evidence and clinical experience, we believe an attempt to make this distinction is unwise. It is dangerous to assume these lesions are benign. Many lesions diagnosed as keratoacanthomas have gone on to behave very aggressively and even to metastasize. We believe all lesions suspected of being keratoacanthomas should be managed by surgical excision and not observed in the hope that spontaneous involution will occur.