ICD-10-CM > C00-D49 > C50-C50 > C50 > C50.6 > C50.61 C50.61 Malignant neoplasm of axillary tail of breast, female Non-Billable/Non-Specific Codes C50.611Malignant neoplasm of axillary tail of right female breastC50.612Malignant neoplasm of axillary tail of left female breastC50.619Malignant neoplasm of axillary tail of unspecified female breast