A in situ carcinoma that involves the lip. The disease is lip carcinoma in situ (Monarch Disease Ontology identifier MONDO_0004636). Also known as: carcinoma in situ of lip, carcinoma in situ of the Lip, lip in situ carcinoma, stage 0 Lip cancer, stage 0 Lip cancer aJCC v6, stage 0 Lip cancer aJCC v6 and v7, stage 0 Lip cancer aJCC v7, stage 0 cancer of Lip.