<unk>  <unk>  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<unk>  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.<unk>  is commonly found on sun-exposed skin, often face, forearms and hands. It is rarely found at a mucocutaneous junction or on mucous membranes.<unk>  may be difficult to distinguish visually from a skin cancer. Under the microscope,<unk>  very closely resembles squamous cell carcinoma. In order to differentiate between the two, almost the entire structure needs to be removed and examined. While some pathologists classify<unk>  as a distinct entity and not a malignancy, about 6% of clinical and histological<unk> s do progress to invasive and aggressive squamous cell cancers; some pathologists may label<unk>  as "well-differentiated squamous cell carcinoma,<unk>  variant", and prompt definitive surgery may be recommended.
Keratoacanthoma
Squamous cell skin cancer
Arsenical keratosis
Acanthoma
Hydrocarbon keratosis
Clear cell acanthoma
White sponge nevus
Generalized trichoepithelioma