Keratoacanthoma is -

• Keratoacanthoma is self healing nodular lesion with central ulceration • More common in men, usually found on the face of 50–70 years old. • Lesions can grow to 1–3 cm over 6 weeks and typically resolve spontaneously over the subsequent 6 months. Etiopathogenesis • Classically a cup-shaped growth that exhibits symmetry about its middle. • Central crater is filled with a plug of keratin. • Unclear etiology (may be caused by HPV infecting a hair follicle) • Associated with smoking and chemical carcinogen exposure). Treatment • Removal of central keratin plug may speed resolution. • Excision is recommended for persistent lesions • Excision scar is often better than that which remains after resolution.