Invasive squamous cell carcinoma initially diagnosed as a giant keratoacanthoma

Keratoacanthoma (KA) is currently considered a benign epithelial neoplasm. We report a patient with a lesion diagnosed as a KA that behaved aggressively like a squamous cell carcinoma (SCC). Similar reports are not uncommon in the literature. Because there are currently no criteria by which KA can be differentiated from SCC in all instances, we prefer to group KAs within the spectrum of well-differentiated SCC. We emphasize excisional surgery as the treatment modality of choice.