Keratoacanthoma

A Keratoacanthoma (KA) is considered a special variant of a well-differentiated squamous cell carcinoma (SCC), which unlike other forms of SCC, may resolve without treatment. Often described as a little volcano, it appears suddenly and is frequently mistaken as a painful pimple with a central crater containing a crusty core. They generally appear as a single lesion, but can also occur in groups or clusters. They are most commonly found on the sun-exposed areas of the skin such as the head, neck, arms, and legs. Other than sun damage, certain medications and immunosuppression can all increase a patient’s risk of developing a KA. Although a KA may disappear on its own, it is often removed by biopsy for diagnosis under the microscope.

As it can be difficult to distinguish these lesions both clinically and histologically from more aggressive forms of SCC, removal is sometimes recommended and can be achieved through curette and cautery (C&C), wide local excision (WLE), or Mohs micrographic surgery (MMS).