ICD-10 Code C50.419 – Malignant neoplasm of upper-outer quadrant of unspecified female breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.419 – Malignant neoplasm of upper-outer quadrant of unspecified female breast
What it is
This code identifies a malignant tumor in the upper-outer quadrant of the female breast when the side is not documented. Use it when the record specifies breast cancer in that quadrant but does not state left or right.
Clinical signs
Clinical features vary; refer to documentation. Commonly documented findings include a breast mass, breast asymmetry, skin or nipple changes, or imaging and biopsy results confirming malignancy in the upper-outer quadrant.
When to use this code
Use C50.419 when the provider documents primary breast cancer in the upper-outer quadrant and the affected side is unspecified. It is appropriate for final diagnoses, pathology reports, or problem lists that clearly identify this location. If laterality is documented, use the more specific code.
Do not use for
Do not use this code for benign breast lesions, metastatic disease to the breast, or cancers in another breast quadrant. Check documentation if the record does not confirm a malignant neoplasm.
Coding tip
Code the site and laterality exactly as documented; if either is missing, query for clarification before assigning a less specific code.