oral cavity carcinoma in situ (MONDO_0000371, a Monarch Disease Ontology term) is a in situ carcinoma that involves the oral cavity. Also known as: carcinoma in situ of mouth, carcinoma in situ of oral cavity, carcinoma in situ of the mouth, carcinoma in situ of the oral cavity, mouth carcinoma in situ, oral cavity in situ carcinoma, stage 0 carcinoma of mouth, stage 0 carcinoma of oral cavity.