C50.9Malignant neoplasm of breast of unspecified site

C50.9 is the ICD-10-CM diagnosis code for malignant neoplasm of breast of unspecified site. It belongs to category C50 (malignant neoplasm of breast), block C50 (malignant neoplasms of breast) and chapter 2 (neoplasms). It is a header code, so it can't be reported by itself; one of its 2 subcodes must be used instead.

Within C50, choose C50.9 (of unspecified site) only when documentation doesn't support a more specific option: neoplasm of nipple and areola (C50.0), neoplasm of central portion of breast (C50.1), neoplasm of upper-inner quadrant of breast (C50.2), neoplasm of lower-inner quadrant of breast (C50.3), neoplasm of upper-outer quadrant of breast (C50.4), neoplasm of lower-outer quadrant of breast (C50.5), neoplasm of axillary tail of breast (C50.6), neoplasm of overlapping sites of breast (C50.8) and 1 more.

To report this condition, pick the subcode that matches the documentation: C50.91 (female) and C50.92 (male).

Use an additional code to identify estrogen, and other hormones and factors receptor status (Z17.-).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.