What is ICD-10 code C7A.022?

C7A.022 is the ICD-10-CM diagnosis code for Malignant carcinoid tumor of the ascending colon. A rare cancer that develops in hormone-producing cells of the ascending colon, the first upward section of the large intestine on the right side of the abdomen. C7A.022 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C7A.022 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.022 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.022 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.022 map to under V28?

C7A.022 maps to CMS-HCC V28 21 (Lymphoma and Other Cancers). The category number and label come from the CMS-HCC V28 model file for payment year 2026.

What does C7A.022 pay in RAF?

C7A.022 carries a community, non-dual, aged (CNA) RAF weight of 0.671 under CMS-HCC V28 for payment year 2026. The weight comes from the CMS V28 relative-factor file, not a hand-typed table.

What is the V28 vs V24 difference for C7A.022?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For C7A.022, V28 maps to Lymphoma and Other Cancers at RAF 0.671 while V24 mapped to Breast, Prostate, and Other Cancers and Tumors at RAF 0.150. Both models can still appear in legacy data and in payer-specific lookback periods.

What documentation supports C7A.022?

The ascending colon runs vertically up the right side of the abdomen; distinguish from transverse and descending portions Colonic carcinoid tumors may present with abdominal symptoms or be found incidentally during colonoscopy Because C7A.022 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score. 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.022: Malignant carcinoid tumor

C7A.022 maps to CMS-HCC V28 21 (RAF 0.671). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC Buddy coding tools

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Code lookupC7A.022Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

C7A.022

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

Malignant carcinoid tumor of the ascending colon

A rare cancer that develops in hormone-producing cells of the ascending colon, the first upward section of the large intestine on the right side of the abdomen.

Buddy Insight

Malignant carcinoid tumor of the ascending colon is a rare neuroendocrine neoplasm of the right colon.

CMS-HCC V28

Mapped

HCC 21

Lymphoma and Other Cancers

RAF 0.671

CMS-HCC V24

Mapped

HCC 12

Breast, Prostate, and Other C...

RAF 0.150

ACA/HHS

Mapped

HCC 12

HHS-HCC 12

Varies by metal level

ESRD/PACE

Mapped

HCC 12

Breast, Prostate, and Other C...

RAF 0.045

RXHCC

Mapped

HCC 22

Cancer, Other Specified Sites

RAF 0.124

Code Book Path

Official

C7A.0Malignant carcinoid tumors

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

C7A.022Malignant carcinoid tumor of the ascending colon

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C7A.022 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C7A.022 in this effective period.

Related Child Codes

Official

C7A.020Malignant carcinoid tumor of the appendix

C7A.021Malignant carcinoid tumor of the cecum

C7A.023Malignant carcinoid tumor of the transverse colon

C7A.024Malignant carcinoid tumor of the descending colon

C7A.025Malignant carcinoid tumor of the sigmoid colon

Includes

Official

ICD-10-CM does not list Includes notes for C7A.022 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C7A.022 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C7A.022 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C7A.022 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C7A.022 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathological confirmation with immunohistochemistry (synaptophysin, chromogranin A)

Tumor size and depth of invasion — transmural involvement increases metastatic risk

Ki-67 index and mitotic rate for WHO grading

Colonoscopic and imaging findings confirming ascending colon location

MEAT Support

HCC Buddy guidance

Pathological confirmation with immunohistochemistry (synaptophysin, chromogranin A)

Tumor size and depth of invasion — transmural involvement increases metastatic risk

Ki-67 index and mitotic rate for WHO grading

Colonoscopic and imaging findings confirming ascending colon location

Audit Caution

HCC Buddy guidance

Confusing ascending colon adenocarcinoma with carcinoid tumor — immunohistochemistry helps differentiate

Coding a cecal carcinoid as ascending colon or vice versa — exact location matters

Not grading the tumor to determine benign (D3A) versus malignant (C7A) classification

Failing to check for carcinoid syndrome symptoms and code E34.0 separately when present

Common Mistakes

HCC Buddy guidance

C18.2 — Primary malignant neoplasm of ascending colon; adenocarcinoma uses C18 codes

C7A.021 — Malignant carcinoid tumor of cecum; the cecum is proximal to the ascending colon

C7A.023 — Malignant carcinoid tumor of transverse colon; the ascending colon is the right-sided vertical segment

D3A.022 — Benign carcinoid tumor of ascending colon; verify malignant behavior pathologically

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.022 an HCC code?

Yes. C7A.022 (Malignant carcinoid tumor of the ascending colon) maps to Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model (and Breast, Prostate, and Other Cancers and Tumors under V24), with a community non-dual aged RAF of 0.671. It is billable for payment year 2026.

Coder answer: C7A.022 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.022
Description: Malignant carcinoid tumor of the ascending colon
HCC (V28): HCC 21 — Lymphoma and Other Cancers
RAF: 0.671
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 21, Lymphoma and Other Cancers

0.671

V24HCC 12, Breast, Prostate, and Other Cancers and Tumors

0.150

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

0.045

RxHCCHCC 22, Cancer, Other Specified Sites

0.124

Each model's RAF is its CMS base weight for that model's standard population, so 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 segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work C7A.022 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C7A.022

For C7A.022 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.022 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C7A.022 is the ICD-10-CM diagnosis code for malignant carcinoid tumor of the ascending colon. A rare cancer that develops in hormone-producing cells of the ascending colon, the first upward section of the large intestine on the right side of the abdomen. C7A.022 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.022 maps to Lymphoma and Other Cancers (HCC 21) with a community, non-dual, aged base RAF weight of 0.671. Under the older CMS-HCC V24 model, C7A.022 maps to Breast, Prostate, and Other Cancers and Tumors (HCC 12) with a community, non-dual, aged base RAF weight of 0.150. 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.

The ascending colon runs vertically up the right side of the abdomen; distinguish from transverse and descending portions. Because C7A.022 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. 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, RAF weights, and MEAT documentation criteria for C7A.022 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•The ascending colon runs vertically up the right side of the abdomen; distinguish from transverse and descending portions
•Colonic carcinoid tumors may present with abdominal symptoms or be found incidentally during colonoscopy

Clinical Significance

Malignant carcinoid tumor of the ascending colon is a rare neuroendocrine neoplasm of the right colon. Ascending colon carcinoids are part of the midgut neuroendocrine tumor family and may produce serotonin, potentially causing carcinoid syndrome when liver metastases are present. They tend to be diagnosed at a larger size compared to appendiceal carcinoids and carry a more guarded prognosis.

Documentation Requirements

✓Pathological confirmation with immunohistochemistry (synaptophysin, chromogranin A)
✓Tumor size and depth of invasion — transmural involvement increases metastatic risk
✓Ki-67 index and mitotic rate for WHO grading
✓Colonoscopic and imaging findings confirming ascending colon location
✓Staging workup — CT, octreotide scan, liver assessment
✓Surgical procedure performed and margin status

Commonly Confused Codes

•C18.2: Primary malignant neoplasm of ascending colon; adenocarcinoma uses C18 codes
•C7A.021: Malignant carcinoid tumor of cecum; the cecum is proximal to the ascending colon
•C7A.023: Malignant carcinoid tumor of transverse colon; the ascending colon is the right-sided vertical segment
•D3A.022: Benign carcinoid tumor of ascending colon; verify malignant behavior pathologically