What is ICD-10 code C7A.024?

C7A.024 is the ICD-10-CM diagnosis code for Malignant carcinoid tumor of the descending colon. A rare cancer that develops in hormone-producing cells of the descending colon, the downward section of the large intestine on the left side of the abdomen. C7A.024 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C7A.024 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. C7A.024 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. C7A.024 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does C7A.024 map to under V28?

C7A.024 maps to CMS-HCC V28 HCC 21 (Lymphoma and Other Cancers). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

What documentation supports C7A.024?

The descending colon runs vertically down the left side of the abdomen; note that C7A.023 is not used (gap in code sequence) Document whether the tumor is in the descending colon proper or extends into the sigmoid region Because C7A.024 maps to an HCC category, the documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. See the MEAT criteria checklist at /meat-criteria for what Monitor, Evaluate, Assess, or Treat looks like in a note. MEAT is generic documentation evidence, not a payer-specific rule.

2026 ICD-10-CM C7A.024: Malignant carcinoid tumor

C7A.024 maps to CMS-HCC V28 21. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

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Code lookupC7A.024Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neuroendocrine tumors (C7A)

C7A.024

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Malignant carcinoid tumor of the descending colon

A rare cancer that develops in hormone-producing cells of the descending colon, the downward section of the large intestine on the left side of the abdomen.

Buddy Insight

Malignant carcinoid tumor of the descending colon is a rare hindgut neuroendocrine neoplasm.

CMS-HCC V28

Mapped

HCC 21

Lymphoma and Other Cancers

Code-level coefficient reference

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 012

HHS-HCC 012 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 12

Breast/Prostate/and Other Can...

Code-level coefficient reference

RXHCC

Mapped

HCC 22

Prostate, Breast, Bladder, an...

Code-level coefficient reference

Code Book Path

Official

C7A.0Malignant carcinoid tumors

C7A.02Malignant carcinoid tumors of the appendix, large intestine, and rectum

C7A.024Malignant carcinoid tumor of the descending colon

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C7A.024 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C7A.024 in this effective period.

Related Child Codes

Official

C7A.020Malignant carcinoid tumor of the appendix

C7A.021Malignant carcinoid tumor of the cecum

C7A.022Malignant carcinoid tumor of the ascending colon

C7A.023Malignant carcinoid tumor of the transverse colon

C7A.025Malignant carcinoid tumor of the sigmoid colon

Includes

Official

ICD-10-CM does not list Includes notes for C7A.024 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C7A.024 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C7A.024 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C7A.024 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C7A.024 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathological confirmation with neuroendocrine markers

WHO tumor grade — Ki-67 index and mitotic rate

Tumor size, depth of invasion, and margin status

Colonoscopy confirming descending colon location

MEAT Support

HCC Buddy guidance

Pathological confirmation with neuroendocrine markers

WHO tumor grade — Ki-67 index and mitotic rate

Tumor size, depth of invasion, and margin status

Colonoscopy confirming descending colon location

Audit Caution

HCC Buddy guidance

Using adenocarcinoma codes for a carcinoid tumor — histological type determines the code category

Confusing descending colon with sigmoid colon location — colonoscopy or operative findings clarify the boundary

Not grading the tumor to determine whether it is benign or malignant by WHO criteria

Missing the hindgut origin significance — these tumors rarely cause carcinoid syndrome

Common Mistakes

HCC Buddy guidance

C18.6 — Primary malignant neoplasm of descending colon; adenocarcinoma uses C18 codes

C7A.023 — Malignant carcinoid tumor of transverse colon; located proximal to the descending colon

C7A.025 — Malignant carcinoid tumor of sigmoid colon; sigmoid is distal to the descending colon

D3A.024 — Benign carcinoid tumor of descending colon; verify malignant versus benign behavior

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is C7A.024 an HCC code?

Yes. C7A.024 (Malignant carcinoid tumor of the descending colon) maps to HCC 21, Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.671. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: C7A.024 is billable and maps to V28 HCC 21, Lymphoma and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C7A.024
Description: Malignant carcinoid tumor of the descending colon
HCC (V28): HCC 21 — Lymphoma and Other Cancers
RAF reference coefficient: 0.671
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 21, Lymphoma and Other Cancers

0.671

ESRDHCC 12, Breast/Prostate/and Other Cancers and Tumors

Not separately weighted

RxHCCHCC 22, Prostate, Breast, Bladder, and Other Cancers and Tumors

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work C7A.024 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for C7A.024

For C7A.024 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed C7A.024 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C7A.024 is the ICD-10-CM diagnosis code for malignant carcinoid tumor of the descending colon. A rare cancer that develops in hormone-producing cells of the descending colon, the downward section of the large intestine on the left side of the abdomen. C7A.024 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neuroendocrine tumors (c7a).

Under the CMS-HCC V28 risk adjustment model, C7A.024 maps to Lymphoma and Other Cancers (HCC 21) with a source-labeled community, non-dual, aged reference coefficient of 0.671. No V24 mapping is shown for C7A.024; use the applicable model and payment year when reviewing the V28 mapping. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

The descending colon runs vertically down the left side of the abdomen; note that C7A.023 is not used (gap in code sequence). Because C7A.024 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for C7A.024 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•The descending colon runs vertically down the left side of the abdomen; note that C7A.023 is not used (gap in code sequence)
•Document whether the tumor is in the descending colon proper or extends into the sigmoid region

Clinical Significance

Malignant carcinoid tumor of the descending colon is a rare hindgut neuroendocrine neoplasm. Hindgut carcinoids (descending colon, sigmoid, rectum) are less likely to produce serotonin and cause carcinoid syndrome compared to midgut tumors. However, they can still metastasize and require surgical resection with careful pathological staging.

Documentation Requirements

✓Pathological confirmation with neuroendocrine markers
✓WHO tumor grade — Ki-67 index and mitotic rate
✓Tumor size, depth of invasion, and margin status
✓Colonoscopy confirming descending colon location
✓Staging workup — CT abdomen/pelvis, liver assessment
✓Surgical approach and extent of resection

Commonly Confused Codes

•C18.6: Primary malignant neoplasm of descending colon; adenocarcinoma uses C18 codes
•C7A.023: Malignant carcinoid tumor of transverse colon; located proximal to the descending colon
•C7A.025: Malignant carcinoid tumor of sigmoid colon; sigmoid is distal to the descending colon
•D3A.024: Benign carcinoid tumor of descending colon; verify malignant versus benign behavior