ICD-10 Code C50.812 – Malignant neoplasm of overlapping sites of left female breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.812 – Malignant neoplasm of overlapping sites of left female breast
What it is
This code identifies a malignant breast tumor in the left female breast that overlaps two or more adjacent sites, so no single subsite fully describes the lesion. Use it when the documentation states overlapping sites rather than a more specific breast location.
Clinical signs
Clinical features vary; refer to documentation. Breast cancer may present as a palpable mass, skin or nipple changes, asymmetry, or abnormal imaging findings, but the chart must support the left-sided overlapping-site primary tumor.
When to use this code
Use C50.812 when the provider documents a primary malignant neoplasm involving overlapping sites of the left female breast. It is appropriate when pathology, imaging, or operative notes indicate the lesion spans more than one breast subsite and the left side is specified. Check documentation if laterality or primary site is unclear.
Do not use for
Do not use this code for benign breast disease, carcinoma in situ, or metastatic disease to the breast. It is also incorrect if the tumor is documented in a single, more specific left breast site.
Coding tip
Confirm that the record states both malignancy and overlapping left breast sites before assigning C50.812.