What is ICD-10 code C7A.029?

C7A.029 is the ICD-10-CM diagnosis code for Malignant carcinoid tumor of the large intestine, unspecified portion. A rare type of cancer that starts in hormone-producing cells of the large intestine, affecting an unspecified area of the colon. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C7A.029 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C7A.029 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.029 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.029 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.

What is the V28 vs V24 difference for C7A.029?

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.029, V28 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors at RAF 0.545 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 should coders know when reporting C7A.029?

Verify the specific portion of the large intestine is documented; if specified, use more specific codes (C7A.020-C7A.028) Carcinoid tumors are neuroendocrine tumors; ensure distinction from adenocarcinoma or other colorectal malignancies Because C7A.029 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.

C7A.029 ICD-10 Code: Malignant carcinoid tumor

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupC7A.029Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

C7A.029

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

Malignant carcinoid tumor of the large intestine, unspecified portion

A rare type of cancer that starts in hormone-producing cells of the large intestine, affecting an unspecified area of the colon.

Buddy Insight

Malignant carcinoid tumor of the large intestine at an unspecified location represents an active neuroendocrine malignancy requiring ongoing oncologic management.

CMS-HCC V28

Mapped

HCC 21

Breast, Prostate, Colorectal ...

RAF 0.545

CMS-HCC V24

Mapped

HCC 12

Breast, Prostate, and Other C...

RAF 0.150

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 12

Breast, Prostate, and Other C...

RAF 0.0

RXHCC

Mapped

HCC 22

Cancer, Other Specified Sites

RAF 0.0

Code Trumping

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Code Book Path

Official

C7A.0Malignant carcinoid tumors

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

C7A.029Malignant carcinoid tumor of the large intestine, unspecified portion

Inclusion Terms

Official

Malignant carcinoid tumor of the colon NOS

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C7A.029 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.024Malignant carcinoid tumor of the descending colon

Includes

Official

ICD-10-CM does not list Includes notes for C7A.029 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C7A.029 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C7A.029 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C7A.029 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C7A.029 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathology report confirming malignant carcinoid (neuroendocrine) histology

Specific portion of the large intestine involved (cecum, ascending colon, transverse colon, descending colon, sigmoid, rectum) — if documented, use site-specific codes C7A.020-C7A.028

Current treatment status (active treatment, surveillance, or palliative care)

Tumor grade (G1 well-differentiated, G2 moderately differentiated, G3 poorly differentiated)

MEAT Support

HCC Buddy guidance

Pathology report confirming malignant carcinoid (neuroendocrine) histology

Specific portion of the large intestine involved (cecum, ascending colon, transverse colon, descending colon, sigmoid, rectum) — if documented, use site-specific codes C7A.020-C7A.028

Current treatment status (active treatment, surveillance, or palliative care)

Tumor grade (G1 well-differentiated, G2 moderately differentiated, G3 poorly differentiated)

Audit Caution

HCC Buddy guidance

Failing to distinguish between adenocarcinoma (C18-C20 codes) and carcinoid tumor (C7A codes) — always check pathology for neuroendocrine histology

Using this unspecified code when the specific colon segment is documented — query for specificity before defaulting to C7A.029

Confusing benign carcinoid (D3A) with malignant carcinoid (C7A) — malignant behavior must be confirmed

Not coding secondary sites separately when metastatic disease is present — use C7B codes for metastatic sites

Common Mistakes

HCC Buddy guidance

C18.9 — Malignant neoplasm of colon, unspecified: Use C18.9 for adenocarcinoma of the colon; C7A.029 is specifically for neuroendocrine (carcinoid) histology

C7A.020-C7A.028 — Site-specific large intestine carcinoid codes: Use these when the exact portion of the large intestine is documented

D3A.029 — Benign carcinoid tumor of the large intestine, unspecified portion: Use D3A codes for benign behavior; C7A codes are for confirmed malignant carcinoid tumors

C7B.09 — Secondary carcinoid tumors of other sites: Use C7B codes only for metastatic/secondary carcinoid, not for the primary tumor

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is C7A.029 an HCC code?

Yes. C7A.029 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors under the CMS-HCC V28 risk adjustment model (and Breast, Prostate, and Other Cancers and Tumors under V24).

HCC Category Mapping

V28HCC 21, Breast, Prostate, Colorectal and Other Cancers and Tumors

0.545

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

0.150

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

0.000

RxHCCHCC 22, Cancer, Other Specified Sites

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.

MEAT Criteria for C7A.029

For C7A.029to 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.029 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

C7A.029 is the ICD-10-CM diagnosis code for malignant carcinoid tumor of the large intestine, unspecified portion. A rare type of cancer that starts in hormone-producing cells of the large intestine, affecting an unspecified area of the colon. C7A.029 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.029 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors (HCC 21) with a community, non-dual, aged base RAF weight of 0.545. Under the older CMS-HCC V24 model, C7A.029 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.

Verify the specific portion of the large intestine is documented; if specified, use more specific codes (C7A.020-C7A.028). Because C7A.029 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.029 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Verify the specific portion of the large intestine is documented; if specified, use more specific codes (C7A.020-C7A.028)
•Carcinoid tumors are neuroendocrine tumors; ensure distinction from adenocarcinoma or other colorectal malignancies

Clinical Significance

Malignant carcinoid tumor of the large intestine at an unspecified location represents an active neuroendocrine malignancy requiring ongoing oncologic management. These tumors can produce serotonin and other vasoactive substances leading to carcinoid syndrome, and their malignant designation confirms invasive or metastatic potential. Accurate capture is critical for risk adjustment as it reflects a patient with active cancer requiring specialized care.

Documentation Requirements

✓Pathology report confirming malignant carcinoid (neuroendocrine) histology
✓Specific portion of the large intestine involved (cecum, ascending colon, transverse colon, descending colon, sigmoid, rectum) — if documented, use site-specific codes C7A.020-C7A.028
✓Current treatment status (active treatment, surveillance, or palliative care)
✓Tumor grade (G1 well-differentiated, G2 moderately differentiated, G3 poorly differentiated)
✓Presence or absence of carcinoid syndrome symptoms (flushing, diarrhea, wheezing)

Commonly Confused Codes

•C18.9 — Malignant neoplasm of colon, unspecified: Use C18.9 for adenocarcinoma of the colon; C7A.029 is specifically for neuroendocrine (carcinoid) histology
•C7A.020-C7A.028 — Site-specific large intestine carcinoid codes: Use these when the exact portion of the large intestine is documented
•D3A.029 — Benign carcinoid tumor of the large intestine, unspecified portion: Use D3A codes for benign behavior; C7A codes are for confirmed malignant carcinoid tumors
•C7B.09 — Secondary carcinoid tumors of other sites: Use C7B codes only for metastatic/secondary carcinoid, not for the primary tumor