ICD-10 Code C50.421 – Malignant neoplasm of upper-outer quadrant of right male breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.421 – Malignant neoplasm of upper-outer quadrant of right male breast
What it is
This code identifies a malignant breast tumor in the upper-outer quadrant of the right breast in a male patient. Use it when documentation specifies both the right side and the upper-outer location.
Clinical signs
Clinical features vary; refer to documentation. Typical findings include a palpable breast mass, nipple changes, skin dimpling, or enlarged regional lymph nodes, but the diagnosis must be confirmed clinically or pathologically.
When to use this code
Use C50.421 when the provider documents primary breast cancer in the upper-outer quadrant of the right male breast. It is appropriate for confirmed malignancy, initial evaluation, or follow-up encounters when that specific site remains the documented diagnosis.
Do not use for
Do not use this code for benign breast disease, unspecified breast cancer site, or female breast malignancies. If the laterality or quadrant is not documented, check documentation before coding.
Coding tip
Verify both male sex and exact breast subsite in the record before assigning C50.421.