Keratoacanthoma By Gregory L Wells, MD, Ada West Dermatology and Dermatopathology Reviewed / Revised Sep 2022 View Patient Education Diagnosis Treatment Prevention Topic Resources Keratoacanthoma Large Keratoacanthoma Keratoacanthomas are round, firm, usually flesh-colored nodules with sharply sloping borders and a characteristic central crater containing keratinous material; they usually resolve spontaneously, but some may be a well-differentiated form of squamous cell carcinoma.