ICD-10 Code C50.4 – Malignant neoplasm of upper-outer quadrant of breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.4 – Malignant neoplasm of upper-outer quadrant of breast
What it is
C50.4 identifies a malignant tumor located in the upper-outer quadrant of the breast. Use it when documentation specifies this breast subsite and confirms breast cancer.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include a palpable breast mass, imaging abnormality, or biopsy-confirmed malignancy in the upper-outer quadrant.
When to use this code
Use this code when the provider documents primary breast cancer in the upper-outer quadrant, including pathology or imaging-supported diagnoses. It is also appropriate when the site is clearly stated in the record and no more specific breast subsite code applies.
Do not use for
Do not use for benign breast lesions, unspecified breast cancer location, or metastatic disease to the breast without primary breast malignancy. Check documentation if the quadrant is not clearly identified.
Coding tip
Code the exact breast quadrant only when it is explicitly documented; otherwise, query or use the unspecified breast cancer code if supported.