ICD-10 Code D01.2 – Carcinoma in situ of rectum (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D01.2 – Carcinoma in situ of rectum
What it is
D01.2 identifies a noninvasive rectal neoplasm confined to the epithelium. It means malignant-appearing cells are present in the rectum, but there is no documented invasion beyond the mucosal layer.
Clinical signs
Clinical features vary; refer to documentation. Diagnosis is usually based on pathology showing carcinoma in situ or an equivalent statement from the treating clinician or pathologist.
When to use this code
Use D01.2 when the record clearly documents carcinoma in situ of the rectum, including pathology or final diagnosis language. Apply it when the lesion is specifically rectal and described as in situ, intraepithelial, or noninvasive. Check documentation if the site or depth of involvement is unclear.
Do not use for
Do not use this code for invasive rectal cancer, dysplasia without carcinoma in situ, or lesions documented only as colon or anus. If the note is nonspecific, check documentation before assigning D01.2.
Coding tip
Code only when both the rectal site and in situ status are explicitly documented.