ICD-10 Code C50.519 – Malignant neoplasm of lower-outer quadrant of unspecified female breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.519 – Malignant neoplasm of lower-outer quadrant of unspecified female breast
What it is
This code identifies a malignant breast tumor located in the lower-outer quadrant of a female breast when laterality is not documented. Use it when the record specifies the quadrant but does not state right or left.
Clinical signs
Findings may include a palpable breast mass, skin or nipple changes, or abnormal imaging suggesting malignancy. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents cancer in the lower-outer quadrant of a female breast and does not identify the side. It is appropriate for confirmed malignant neoplasm, pathology-supported diagnosis, or oncology problem lists. If laterality is documented, choose the more specific code.
Do not use for
Do not use this code for benign breast lesions, in situ disease, or unspecified breast cancer without quadrant detail. Check documentation if the note does not clearly support malignancy and location.
Coding tip
Verify both the quadrant and the absence of laterality before assigning C50.519.