ICD-10 Code D05 – Carcinoma in situ of breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D05 – Carcinoma in situ of breast
What it is
D05 identifies carcinoma in situ of the breast, a noninvasive breast cancer confined to the ducts or lobules. It means abnormal cells are present but have not spread beyond the breast tissue where they started.
Clinical signs
Clinical features vary; refer to documentation. Cases are often found on breast imaging or biopsy, and pathology should confirm the in situ nature of the lesion.
When to use this code
Use D05 when the provider documents carcinoma in situ of the breast without invasion. It applies to confirmed ductal or lobular in situ disease, including records that state breast cancer in situ. If the note is unclear about laterality or subtype, check documentation.
Do not use for
Do not use D05 for invasive breast carcinoma or for benign breast lesions. If the record describes only atypia, dysplasia, or a suspicious mass without confirmed in situ malignancy, this code is not appropriate.
Coding tip
Confirm the pathology wording; “in situ” must be documented to support D05.