Is it an SCC or keratoacanthoma?
Histology is the gold standard in diagnosing a keratoacanthoma. A deep biopsy specimen that preferably includes part or full subcutaneous fat with excision of the entire lesion should allow for good histologic interpretation and diagnosis. Keratoacanthoma presents as a downgrowth of well-differentiated squamous epithelium. However, even with a well-performed biopsy, the diagnosis of keratoacanthoma remains challenging due to the lack of sufficient sensitive or specific histological features that can distinguish between keratoacanthomas and SCCs. As a rule, a normal surface epithelium surrounding the keratin plug with sharp demarcation between tumor and stroma favors keratoacanthoma, whereas ulceration, numerous mitoses, and marked pleomorphism/anaplasia favor SCC. Because of the lack of a universal diagnostic criterion, several experts recommend that all keratoacanthomas be considered potential SCCs and thus treated as such.1,2 When in doubt, cut it out Although the natural course of a
