ICD-10 Code C50.321 – Malignant neoplasm of lower-inner quadrant of right male breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.321 – Malignant neoplasm of lower-inner quadrant of right male breast
What it is
This code identifies a malignant tumor located in the lower-inner quadrant of the right male breast. Use it when documentation clearly states both the site and that the patient is male.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include a palpable breast mass, nipple changes, or imaging and biopsy results confirming malignancy.
When to use this code
Use C50.321 when the provider documents primary breast cancer in the lower-inner quadrant of the right breast in a male patient. It also applies when pathology or imaging supports that exact anatomic site and laterality.
If the record only says “right breast cancer” or does not specify quadrant, check documentation before assigning this code. Use the most precise breast malignancy code available from the note.
Do not use for
Do not use this code for benign breast lesions, uncertain masses, or malignancies in a different breast quadrant. Check documentation if the site, laterality, or sex is unclear.
Coding tip
Verify quadrant, laterality, and male sex in the source note before coding; missing site detail usually requires a more general breast cancer code.