Excludes1 pair
C44- vs C46.0
C44 and C46.0 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.
The official note, declared on C44
Kaposi's sarcoma of skin (C46.0)
C44
Other and unspecified malignant neoplasm of skin
Not billable
- Chapter 2
- Neoplasms
- Section
- C43-C44
Use when the record says
- malignant neoplasm of sebaceous glands
- malignant neoplasm of sweat glands
C46.0
Kaposi's sarcoma of skin
Billable
- Chapter 2
- Neoplasms
- Section
- C45-C49
Indexed under
- Kaposi's › sarcoma › skin (multiple sites)
- Sarcoma › Kaposi's › skin
Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027