ICD-10 Code D00 – Carcinoma in situ of oral cavity, esophagus and stomach (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D00 – Carcinoma in situ of oral cavity, esophagus and stomach
What it is
D00 identifies carcinoma in situ in the oral cavity, esophagus, or stomach. It means abnormal cells are present in the lining but have not invaded deeper tissue.
Clinical signs
Clinical features vary; refer to documentation. Diagnosis is usually based on pathology showing in situ disease without invasion, and the site should be clearly documented.
When to use this code
Use D00 when the provider documents carcinoma in situ at one of these upper digestive sites. It fits biopsy-confirmed in situ lesions, including cases described as severe dysplasia or intraepithelial neoplasia when the record supports that interpretation. Check the exact anatomic site before coding.
Do not use for
Do not use D00 for invasive cancer, because that requires a different malignant neoplasm code. Do not assign it when the site is unspecified or when documentation does not confirm in situ disease.
Coding tip
Always verify both the pathology wording and the exact site, since D00 is site-specific and limited to in situ disease.