C50.91
Malignant neoplasm of breast of unspecified site, female
Not billable — category only FY2026 2025-10-01 → 2026-09-30
This is the unspecified option. 1 more
specific code sit alongside it. Worth
checking whether the documentation supports one of them.
Exclusions 1 never code together
Instructional notes 12
C50code
Includes
- connective tissue of breast
- Paget's disease of breast
- Paget's disease of nipple
Use additional code
- code to identify estrogen, and other hormones and factors receptor status (Z17.-)Z17.-
C00-D49chapter
Notes
- Functional activity
- All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
- Morphology [Histology]
- Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
- Primary malignant neoplasms overlapping site boundaries
- A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
- Malignant neoplasm of ectopic tissue
- Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).C25.9
Index entries leading here 5
- Adenocarcinoma — see also Neoplasm, malignant, by site
- Disease, diseased — see also Syndrome
- Cancer — see also Neoplasm, by site, malignant
- breast C50.91
- Carcinoma-in-situ — see also Neoplasm, in situ, by site
- Carcinoma (malignant) — see also Neoplasm, by site, malignant
- ductular, infiltrating
- unspecified site (female) C50.91
- infiltrating
- inflammatory
- unspecified site (female) C50.91
- intraductal (noninfiltrating)
- papillary
- with invasion
- unspecified site (female) C50.91
- with invasion
- papillary
- lipid-rich (female) C50.91
- lobular (infiltrating)
- medullary
- with
- lymphoid stroma
- unspecified site (female) C50.91
- lymphoid stroma
- with
- papillary
- intraductal (noninfiltrating)
- with invasion
- unspecified site (female) C50.91
- with invasion
- intraductal (noninfiltrating)
- duct (cell)
- ductal
- with lobular
- unspecified site (female) C50.91
- with lobular
- ductular, infiltrating
Alongside this code 1 same parent — C50.9
Subordinate codes 3
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.