Keratoacanthoma of the Lip: A Case Report with Emphasis on Histogenesis

The document discussed keratoacanthoma (KA), a benign epithelial tumor that typically appears on sun-exposed skin and resembles a low-grade squamous cell carcinoma. It highlighted the role of actinic rays in its development and noted that KAs usually originate from hair follicles. However, the report focused on cases where KAs occur on mucous membranes, such as the lip, where hair follicles are absent. The study aimed to identify the cells responsible for initiating KAs in these unusual locations, suggesting a different histogenesis for mucosal KAs compared to those on skin.