ICD-10-CM > C00-D49 > C50-C50 > C50 > C50.5 > C50.51 C50.51 Malignant neoplasm of lower-outer quadrant of breast, female Non-Billable/Non-Specific Codes C50.511Malignant neoplasm of lower-outer quadrant of right female breastC50.512Malignant neoplasm of lower-outer quadrant of left female breastC50.519Malignant neoplasm of lower-outer quadrant of unspecified female breast