ICD-10 Code C50.329 – Malignant neoplasm of lower-inner quadrant of unspecified male breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.329 – Malignant neoplasm of lower-inner quadrant of unspecified male breast
What it is
This code identifies a malignant tumor in the lower-inner quadrant of a male breast when laterality is not documented. Use it for primary breast cancer arising in that specified breast region.
Clinical signs
Typical findings include a palpable breast mass, nipple changes, skin dimpling, or localized pain. Clinical features vary; refer to documentation and pathology when available.
When to use this code
Use C50.329 when the provider documents breast cancer in the lower-inner quadrant of an unspecified male breast and no left or right side is stated. It is appropriate for confirmed malignant neoplasm, including biopsy or imaging-supported diagnoses. If laterality is later clarified, update coding accordingly.
Do not use for
Do not use this code for benign breast lesions, carcinoma in situ, or metastatic disease to the breast. If the record does not specify the lower-inner quadrant or male sex, check documentation.
Coding tip
Verify both quadrant and laterality in the note before assigning C50.329.