Keratoacanthoma

Common card · No. 392585

Keratoacanthoma (KA) is a common low-grade (unlikely to metastasize or invade) rapidly-growing skin tumour that is believed to originate from the hair follicle (pilosebaceous unit) and can resemble squamous cell carcinoma. The defining characteristic of a keratoacanthoma is that it is dome-shaped, symmetrical, surrounded by a smooth wall of inflamed skin, and capped with keratin scales and debris. It grows rapidly, reaching a large size within days or weeks, and if untreated for months will almost always starve itself of nourishment, necrose (die), slough, and heal with scarring. Keratoacanthoma is commonly found on sun-exposed skin, often face, forearms and hands. It is rarely found at a mucocutaneous junction or on mucous membranes. Keratoacanthoma may be difficult to distinguish visually from a skin cancer. Under the microscope, keratoacanthoma very closely resembles squamous cell carcinoma. In order to differentiate between the two, almost the entire structure needs to be removed and...

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