ICD-10 Code D01.0 – Carcinoma in situ of colon (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D01.0 – Carcinoma in situ of colon
What it is
D01.0 identifies carcinoma in situ of the colon, meaning abnormal cells are confined to the lining and have not invaded deeper tissue. It is a precancerous or very early cancer diagnosis.
Clinical signs
Clinical features vary; refer to documentation. This code may be supported by pathology describing malignant-appearing cells limited to the colonic mucosa without invasion.
When to use this code
Use D01.0 when the provider documents carcinoma in situ of the colon, or pathology confirms in situ disease in the colon. Code it for a confirmed diagnosis, not for a nonspecific colon lesion or suspected malignancy. If the record is unclear about site or invasion, check documentation.
Do not use for
Do not use this code for invasive colon cancer, benign polyps, or dysplasia without a carcinoma in situ diagnosis. If the pathology does not specify the colon or in situ status, do not assume D01.0.
Coding tip
Verify the pathology report and provider impression together before assigning D01.0.