ICD-10 Code C50.61 – Malignant neoplasm of axillary tail of breast, female (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C50.61 – Malignant neoplasm of axillary tail of breast, female
What it is
This code identifies a malignant breast tumor located in the axillary tail, the portion of breast tissue that extends toward the armpit. Use it for female patients when the documentation specifies this exact site.
Clinical signs
Typical findings include a breast or axillary-tail mass, possible skin or tissue distortion, and imaging or biopsy evidence of malignancy. Clinical features vary; refer to documentation.
When to use this code
Use C50.61 when the provider documents primary cancer arising in the axillary tail of the breast in a female patient. It is also appropriate when pathology, imaging, or operative notes clearly identify that location. If the site is described only as breast cancer without a specific quadrant or tail, check documentation.
Do not use for
Do not use this code for male breast cancer or for tumors in other breast quadrants. Do not use it when the lesion is metastatic to the breast or when the axillary mass is not documented as breast tissue.
Coding tip
Verify that the record names the axillary tail specifically before assigning C50.61.