Keratoacanthomas are a low-grade subtype of squamous cell carcinoma
. The majority occur in sun-exposed skin, usually on the hands or face. They are typically skin colored or slightly red when they first develop, but they can grow rapidly to 1 to 2 cm in size. Most will spontaneously get better within 1 year, but they almost always scar after healing. Removal by surgery (or sometimes by radiation) is recommended. In cases not appropriate for excision (due to their size or location), keratoacanthomas may be treated with 5-fluorouracil
, either as a cream or by injection.