C18 vs C46.4
C18 (Malignant neoplasm of colon) compared with C46.4 (Kaposi's sarcoma of gastrointestinal sites), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. C18 carries an Excludes1 note covering C46.4: “Kaposi's sarcoma of gastrointestinal sites (C46.4)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| C18Malignant neoplasm of colon | C46.4Kaposi's sarcoma of gastrointestinal sites | |
|---|---|---|
| Billing status | Non-billable header | Billable |
| Classification | C00-D49 — Neoplasms (C00-D49) | C00-D49 — Neoplasms (C00-D49) |
| Definition | Malignant neoplasm of colon is a non-billable ICD-10-CM category code (C18). | Kaposi's sarcoma of gastrointestinal sites is a billable ICD-10-CM diagnosis code (C46.4). |
| Code first | — | any human immunodeficiency virus [HIV] disease (B20) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources