ICD-10 Code D05.0 – Lobular carcinoma in situ of breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D05.0 – Lobular carcinoma in situ of breast
What it is
D05.0 identifies lobular carcinoma in situ (LCIS) of the breast, a noninvasive abnormal growth in the lobules. It is a pathologic diagnosis, not invasive breast cancer.
Clinical signs
Clinical features vary; refer to documentation. LCIS is often found incidentally on biopsy, and imaging or exam findings may be absent or nonspecific.
When to use this code
Use D05.0 when the provider documents LCIS of the breast, including pathology-confirmed in situ disease. Code it for the affected breast when the record supports that diagnosis. If the note only says atypia, high-risk lesion, or another uncertain finding, check documentation before assigning this code.
Do not use for
Do not use D05.0 for invasive lobular carcinoma or for ductal carcinoma in situ. If the record describes a different breast lesion or the pathology is unclear, check documentation.
Coding tip
Assign this code only from explicit provider or pathology documentation of lobular carcinoma in situ.