is a rare inflammatory disorder of the lip . It is mainly characterized by swelling of the lip with hyperplasia of the salivary glands; secretion of a clear, thick mucus; and variable inflammation. Enlargement and chronic exposure of the mucous membrane on the lower lip becomes affected by the environment, leading to erosion, ulceration, crusting, and, occasionally, infection. It occurs typically in the lower lip of adult males, but has been described in the upper lip, or in teenagers. In Caucasians, it is associated with a relatively high incidence of squamous cell carcinoma of the lip. Although there may be a genetic susceptibility, no definitive cause has been established. Treatment may include surgical excision by vermilionectomy (sometimes called a lip shave), but treatment varies for each individual. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.