Monarch Disease Ontology id MONDO_0004708 (esophagus carcinoma in situ) is stage 0 includes: For squamous cell carcinoma: Tis (HGD), N0, M0, G1, GX, Tumor location: Any. For adenocarcinoma: Tis (HGD), N0, M0, G1, GX. Tis: High-grade dysplasia. N0: No regional lymph node metastasis. M0: No distant metastasis. G1: Well differentiated. GX: Grade cannot be assessed-stage grouping as G1. Tumor location: Location of the primary cancer site is defined by the position of the upper (proximal) edge of the tumor in the esophagus. (AJCC 7th ed.). Also known as: carcinoma in situ of esophagus, carcinoma in situ of oesophagus, esophageal carcinoma in situ, esophageal carcinoma in situ aJCC v7, esophagus in situ carcinoma, oesophagus in situ carcinoma, severe esophageal dysplasia, severe esophageal dysplasia aJCC v7.