ICD-10 Code C50.619 – Malignant neoplasm of axillary tail of unspecified female breast (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.619 – Malignant neoplasm of axillary tail of unspecified female breast
What it is
This code identifies a malignant tumor in the axillary tail of the female breast when the side is not documented. Use it for breast cancer arising in the upper outer extension toward the axilla.
Clinical signs
Findings may include a breast or axillary-tail mass, asymmetry, skin change, or nipple-related abnormalities. Clinical features vary; refer to documentation and pathology when available.
When to use this code
Use this code when the provider documents primary breast cancer in the axillary tail and does not specify right or left. It may appear on pathology, oncology, or surgical records. If laterality is documented, choose the more specific code.
Do not use for
Do not use it for benign breast disease, metastatic disease to the breast, or cancers in a different breast quadrant. Check documentation if the axillary tail is not clearly identified.
Coding tip
Verify both the breast site and laterality; unspecified laterality is appropriate only when the record truly lacks that detail.