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.

Which HCC does C7A.029 map to under V28?

C7A.029 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.

2026 ICD-10-CM C7A.029: Malignant carcinoid tumor

C7A.029 maps to CMS-HCC V28 21. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software

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Code lookupC7A.029

Effective 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.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

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

Inclusion Terms

Official

Malignant carcinoid tumor of the colon NOS

Excludes 2

Official

malignant pancreatic islet cell tumors (C25.4)Inherited from C7A
Merkel cell carcinoma (C4A.-)Inherited from C7A

Related 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

No Includes notes are included in this display for C7A.029. Check the code and parent instructions in the Code Book.

Excludes 1

Official

No Excludes 1 notes are included in this display for C7A.029. Check the code and parent instructions in the Code Book.

Code First

Official

No Code First sequencing instructions are included in this display for C7A.029. Check the code and parent instructions in the Code Book.

Use Additional

Official

code to identify any associated endocrine syndrome, such as:Inherited from C7A
carcinoid syndrome (E34.00)Inherited from C7A

Code Also

Official

any associated multiple endocrine neoplasia [MEN] syndromes (E31.2-)Inherited from C7A

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

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.029 an HCC code?

Yes. C7A.029 (Malignant carcinoid tumor of the large intestine, unspecified portion) 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.029 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.029
Description: Malignant carcinoid tumor of the large intestine, unspecified portion
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.029 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C7A.029

For C7A.029, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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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 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.029; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. 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.

Verify the specific portion of the large intestine is documented; if specified, use more specific codes (C7A.020-C7A.028). For C7A.029, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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.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