Breast Cancer ICD-10-CM codes

Category C50 is built in three parts. The fourth character is the site within the breast: C50.0 nipple and areola, C50.1 central portion, C50.2 to C50.5 the four quadrants (C50.4 upper-outer is the most frequent), C50.6 axillary tail, C50.8 overlapping sites, and C50.9 unspecified site. The fifth character is sex (1 female, 2 male) and the sixth is laterality (1 right, 2 left, 9 unspecified). C50.919 is unspecified site of unspecified female breast; when the record documents laterality, C50.911 (right) or C50.912 (left) must be used instead.

Ductal carcinoma in situ is D05.1- and lobular carcinoma in situ is D05.0-, with the fifth character for laterality. Do not use C50 for in situ disease. Receptor status is reported with Z17: Z17.0 estrogen receptor positive, Z17.1 estrogen receptor negative, or the combined codes Z17.410 (hormone receptor positive, HER2 positive) and Z17.411 (hormone receptor positive, HER2 negative). These are additional codes and are sequenced after the C50 code.

A patient with a current breast cancer who is still receiving treatment directed at the cancer, including tamoxifen or an aromatase inhibitor, keeps the C50 code. Add Z79.810 for long-term use of a selective estrogen receptor modulator or Z79.811 for an aromatase inhibitor. When the cancer has been excised with no further treatment directed at it and no evidence of disease, report Z85.3 (personal history of malignant neoplasm of breast) and Z90.11, Z90.12, or Z90.13 for the acquired absence of the breast.

When a patient is admitted solely for chemotherapy, Z51.11 is the principal diagnosis and C50.- follows. Z15.01 reports a confirmed BRCA or other genetic susceptibility to breast cancer, and Z40.01 is the prophylactic mastectomy encounter in such a patient. Metastatic spread is coded separately with C77.3 (axillary lymph nodes), C79.51 (bone), or the other C77 to C79 sites.