C18.9 is the authoritative medical code for Malignant neoplasm of colon, unspecified. This classification is used in medical billing and clinical recording to specify the clinical criteria for malignant neoplasm of colon, unspecified (ICD-10-CM C18.9), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Official Registry Overview & Definition
Malignant neoplasm of colon, unspecified is a billable ICD-10-CM diagnosis code C18.9. Inclusion terms: Malignant neoplasm of large intestine NOS. Excludes1 (not coded here): malignant carcinoid tumors of the colon C7A.02-; Kaposi's sarcoma of gastrointestinal sites C46.4. Excludes2 (not included here): gastrointestinal stromal tumors C49.A-.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for C18.9 in the official ICD-10-CM tabular list.
Inclusion Terms
Alternative terms the tabular list files under this code.
- Malignant neoplasm of large intestine NOS
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- malignant carcinoid tumors of the colon C7A.02-
- Kaposi's sarcoma of gastrointestinal sites C46.4
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- gastrointestinal stromal tumors C49.A-
Frequently Asked Questions (FAQ) & Clinical Guidance
What can't be coded together with C18.9?
Per Excludes1 instructions, C18.9 must not be reported with: malignant carcinoid tumors of the colon (C7A.02-); Kaposi's sarcoma of gastrointestinal sites (C46.4).
Can C18.9 be reported alongside related conditions?
Per Excludes2 instructions, C18.9 and the following may both be reported when both are present: gastrointestinal stromal tumors (C49.A-).
What conditions are included under C18.9?
Malignant neoplasm of colon, unspecified includes: Malignant neoplasm of large intestine NOS.
Codes in This Family (10)
Official ICD-10-CM classifications in the same code family as C18.9, with their registry titles.
- C18 — Malignant neoplasm of colon
- C18.0 — Malignant neoplasm of cecum
- C18.1 — Malignant neoplasm of appendix
- C18.2 — Malignant neoplasm of ascending colon
- C18.3 — Malignant neoplasm of hepatic flexure
- C18.4 — Malignant neoplasm of transverse colon
- C18.5 — Malignant neoplasm of splenic flexure
- C18.6 — Malignant neoplasm of descending colon
- C18.7 — Malignant neoplasm of sigmoid colon
- C18.8 — Malignant neoplasm of overlapping sites of colon
Indexed Clinical Terms (4)
Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.
- Adenocarcinoma, in, adenomatous, polyposis coli
- Carcinoma (malignant), in, adenomatous, polyposis coli
- Polyposis, coli, adenocarcinoma in
- Polyposis, coli, carcinoma in
Neoplasm Table Sites (3)
Anatomical sites from the official ICD-10-CM Table of Neoplasms that map to this code, with the matching behavior column.
- Neoplasm, neoplastic, colon — Malignant, Primary
- Neoplasm, neoplastic, intestine, intestinal, large — Malignant, Primary
- Neoplasm, neoplastic, intestine, intestinal, large, colon — Malignant, Primary
Related Codes & Numerical Sequence (Crawl Map)
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures:
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