ICD-10 Code C50.311 – Malignant neoplasm of lower-inner quadrant of right female breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.311 – Malignant neoplasm of lower-inner quadrant of right female breast
What it is
This code identifies a malignant tumor in the lower-inner quadrant of the right breast in a female patient. Use it when the documentation specifies both the right side and the lower-inner breast location.
Clinical signs
Clinical features vary; refer to documentation. Breast cancer may present as a palpable mass, skin or nipple changes, breast asymmetry, or abnormal imaging findings confirmed by pathology.
When to use this code
Use C50.311 when the provider documents primary malignancy in the lower-inner quadrant of the right female breast. It is appropriate for confirmed breast cancer cases, including biopsy-proven disease and oncology follow-up records that specify this exact site. Check documentation if laterality or quadrant is unclear.
Do not use for
Do not use this code for left breast disease, unspecified breast location, or benign breast lesions. If the record describes metastatic disease only, or the site is not clearly documented, check documentation.
Coding tip
Verify both laterality and quadrant before assigning C50.311.