A benign, non-neoplastic, usually self-limiting epithelial lesion closely resembling squamous cell carcinoma clinically and histopathologically. It occurs in solitary, multiple, and eruptive forms. The solitary and multiple forms occur on sunlight exposed areas and are identical histologically; they affect primarily white males. The eruptive form usually involves both sexes and appears as a generalized papular eruption.

A dome-shaped, rapidly growing skin lesion composed of well differentiated squamous cells. It represents a proliferation of the infundibular epithelium of the hair follicle and its morphologic distinction from a well differentiated carcinoma may be difficult or impossible. Keratoacanthomas affect males more frequently than females and the majority tend to regress spontaneously. It has been suggested that keratoacanthoma represents a distinct subtype of squamous cell carcinoma of the skin.

A rapidly growing, dome-shaped skin tumor that usually occurs on sun-exposed areas of the body, especially around the head and neck. Keratoacanthoma occurs more often in males. Although in most patients it goes away on its own, in a few patients it comes back. Rarely, it may spread to other parts of the body.

Benign papular lesion with a superficial crater filled with a keratin plug, usually on the face.

Keratoacanthoma (KA) is a common benign epithelial tumour that originates from the pilosebaceous glands. In most cases, it is characterized by rapid evolution, followed by spontaneous resolution over 4 to 6 months. KA usually presents as a solitary flesh-coloured nodule with a central keratin plug on the sun-exposed skin of elderly individuals.

Keratoacanthomas are round, firm, usually flesh-colored nodules with sharply sloping borders and a characteristic central crater containing keratinous material; they usually resolve spontaneously, but some may be a well-differentiated form of squamous cell carcinoma.

Keratoacanthoma (KA) is a relatively common low-grade tumor that originates in the pilosebaceous glands and closely resembles squamous cell carcinoma (SCC). In fact, strong arguments support classifying keratoacanthoma as a variant of invasive SCC.