Keratoacanthoma

Keratoacanthoma (KA) is a common low-grade (unlikely to metastasize or invade) skin tumour that is believed to originate from the neck of the hair follicle. Many pathologists consider it to be a form of squamous cell carcinoma (SCC). The pathologist often labels KA as "well-differentiated squamous cell carcinoma, keratoacanthoma variant", because about 6% of KA manifest itself as squamous cell carcinoma when left untreated. KA is commonly found on sun-exposed skin, and often is seen on the face, forearms and hands.