ICD-10 Code C50.429 – Malignant neoplasm of upper-outer quadrant of unspecified male breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.429 – Malignant neoplasm of upper-outer quadrant of unspecified male breast
What it is
This code identifies a malignant tumor in the upper-outer quadrant of a male breast, with the side not specified. Use it when the record documents breast cancer in that location but does not state left or right.
Clinical signs
Clinical features vary; refer to documentation. Commonly documented findings include a breast mass, nipple changes, skin dimpling, or axillary node involvement, but you should code only what is clearly recorded.
When to use this code
Use C50.429 when the provider documents malignant neoplasm of the upper-outer quadrant of an unspecified male breast and laterality is not available. It also fits when the diagnosis is confirmed, but the chart does not specify left or right. Check documentation if the note only says breast cancer without quadrant detail.
Do not use for
Do not use this code if the cancer is in a different breast quadrant or if the side is documented elsewhere. Do not assign it for benign breast disease, metastasis to the breast, or unspecified breast cancer without quadrant information.
Coding tip
Capture laterality and quadrant from the most specific provider documentation before defaulting to an unspecified code.