ICD-10 Code C50.529 – Malignant neoplasm of lower-outer quadrant of unspecified male breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.529 – Malignant neoplasm of lower-outer quadrant of unspecified male breast
What it is
This code identifies a malignant tumor in the lower-outer quadrant of a male breast when the side is not documented. Use it for breast cancer records that specify this anatomic location but do not state left or right.
Clinical signs
Clinical features vary; refer to documentation. Commonly, records describe a breast mass, nipple changes, skin dimpling, or axillary node findings, but the diagnosis should be supported by pathology or specialist assessment.
When to use this code
Use C50.529 when the provider documents primary breast cancer in the lower-outer quadrant of an unspecified male breast. It is appropriate for confirmed malignant neoplasm when laterality is not recorded or cannot be determined from the note. If the chart names another quadrant or a different breast site, choose the more specific code.
Do not use for
Do not use this code for benign breast disease, breast mass without confirmed malignancy, or female breast cancer. If the documentation gives a different quadrant, laterality, or metastatic site only, check documentation.
Coding tip
Query for laterality and exact breast site whenever possible; unspecified codes are less precise and may affect reporting.