Monarch Disease Ontology term MONDO_0021297 (carcinoma in situ of nasopharynx) is a in situ carcinoma that involves the nasopharynx. Also known as: carcinoma in situ of the nasopharynx, nasopharyngeal carcinoma in situ, nasopharynx carcinoma in situ, nasopharynx in situ carcinoma, stage 0 carcinoma of nasopharynx, stage 0 carcinoma of the nasopharynx, stage 0 nasopharyngeal cancer, stage 0 nasopharyngeal carcinoma.