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C7A.023 ICD-10-CM Code: Malignant carcinoid tumor of the transverse colon

C7A.023 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.023

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

C7A.023

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

Malignant carcinoid tumor of the transverse colon

A rare type of cancer that starts in hormone-producing cells of the transverse colon (the middle section of the large intestine). This tumor has the potential to spread to other parts of the body.

Buddy the Bee presenting code insight

Buddy Insight

Malignant carcinoid tumor of the transverse colon is a rare neuroendocrine neoplasm in the horizontal segment of the large intestine.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 21

Coefficient HCC 21: 0.671 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 012

Code-level coefficient reference

ESRD/PACE

HCC 12

Code-level coefficient reference

RXHCC

HCC 22

Code-level coefficient reference

Code Book Path

Official
C7A.0Malignant carcinoid tumorsC7A.02Malignant carcinoid tumors of the appendix, large intestine, and rectumC7A.023Malignant carcinoid tumor of the transverse colon

Inclusion Terms

Official

No inclusion terms are included in this display for C7A.023. Check the code and parent instructions in the Code Book.

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 appendixC7A.021Malignant carcinoid tumor of the cecumC7A.022Malignant carcinoid tumor of the ascending colonC7A.024Malignant carcinoid tumor of the descending colonC7A.025Malignant carcinoid tumor of the sigmoid colon

Includes

Official

No Includes notes are included in this display for C7A.023. Check the code and parent instructions in the Code Book.

Excludes 1

Official

No Excludes 1 notes are included in this display for C7A.023. 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.023. 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
Pathological confirmation of neuroendocrine tumor with malignant features
Tumor grade — Ki-67 index and mitotic count
Tumor size, depth of invasion, and lymphovascular invasion status
Colonoscopic location confirmed as transverse colon versus hepatic or splenic flexure

MEAT Support

HCC Buddy guidance
Pathological confirmation of neuroendocrine tumor with malignant features
Tumor grade — Ki-67 index and mitotic count
Tumor size, depth of invasion, and lymphovascular invasion status
Colonoscopic location confirmed as transverse colon versus hepatic or splenic flexure

Audit Caution

HCC Buddy guidance
Confusing transverse colon with hepatic or splenic flexure locations
Using adenocarcinoma codes (C18.4) for carcinoid tumors — different histological types require different code categories
Not distinguishing benign from malignant neuroendocrine tumors based on WHO grading criteria
Failing to assess for carcinoid syndrome and code it separately when present

Common Mistakes

HCC Buddy guidance
C18.4 — Primary malignant neoplasm of transverse colon; adenocarcinoma of the transverse colon uses different coding
C7A.022 — Malignant carcinoid tumor of ascending colon; located proximal to the transverse colon
C7A.024 — Malignant carcinoid tumor of descending colon; located distal to the transverse colon
D3A.023 — Benign carcinoid tumor of transverse colon; confirm malignant behavior before coding C7A.023

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.023 an HCC code?

Yes. C7A.023 (Malignant carcinoid tumor of the transverse 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.023 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.023
Description
Malignant carcinoid tumor of the transverse 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.023 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C7A.023

For C7A.023, 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.023 is the ICD-10-CM diagnosis code for malignant carcinoid tumor of the transverse colon. A rare type of cancer that starts in hormone-producing cells of the transverse colon (the middle section of the large intestine). This tumor has the potential to spread to other parts of the body. C7A.023 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.023 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.023; 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 site is documented as transverse colon; carcinoid tumors of different colon segments have different codes (C7A.021 for cecum, C7A.022 for ascending colon, C7A.024 for descending colon, etc.). For C7A.023, 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.023 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Verify the specific site is documented as transverse colon; carcinoid tumors of different colon segments have different codes (C7A.021 for cecum, C7A.022 for ascending colon, C7A.024 for descending colon, etc.)
  • •This code includes the malignant behavior; do not add a separate malignancy code. Confirm whether metastasis is present and code accordingly with additional codes if documented.

Clinical Significance

Malignant carcinoid tumor of the transverse colon is a rare neuroendocrine neoplasm in the horizontal segment of the large intestine. Transverse colon carcinoids straddle the embryological boundary between midgut and hindgut, which can affect their hormone production profile and clinical behavior. They are typically discovered during colonoscopy or on imaging for abdominal symptoms.

Documentation Requirements

  • ✓Pathological confirmation of neuroendocrine tumor with malignant features
  • ✓Tumor grade — Ki-67 index and mitotic count
  • ✓Tumor size, depth of invasion, and lymphovascular invasion status
  • ✓Colonoscopic location confirmed as transverse colon versus hepatic or splenic flexure
  • ✓Staging — CT, octreotide scan for metastatic assessment
  • ✓Biochemical markers — chromogranin A, 5-HIAA

Commonly Confused Codes

  • •C18.4: Primary malignant neoplasm of transverse colon; adenocarcinoma of the transverse colon uses different coding
  • •C7A.022: Malignant carcinoid tumor of ascending colon; located proximal to the transverse colon
  • •C7A.024: Malignant carcinoid tumor of descending colon; located distal to the transverse colon
  • •D3A.023: Benign carcinoid tumor of transverse colon; confirm malignant behavior before coding C7A.023

Child Codes

C7A.020Malignant carcinoid tumor of the appendix
HCC 21
C7A.021Malignant carcinoid tumor of the cecum
HCC 21
C7A.022Malignant carcinoid tumor of the ascending colon
HCC 21
C7A.023Malignant carcinoid tumor of the transverse colon
HCC 21
C7A.024Malignant carcinoid tumor of the descending colon
HCC 21
C7A.025Malignant carcinoid tumor of the sigmoid colon
HCC 21
C7A.026Malignant carcinoid tumor of the rectum
HCC 21
C7A.029Malignant carcinoid tumor of the large intestine, unspecified portion
HCC 21

Code Hierarchy

└C7AMalignant neuroendocrine tumors└C7A.0Malignant carcinoid tumors└C7A.02Malignant carcinoid tumors of the appendix, large intestine, and rectum└C7A.023Malignant carcinoid tumor of the transverse colon
└C7A.023Malignant carcinoid tumor of the transverse colon

Also searched as

  • C7A 023
  • C7A023

For C7A.023, 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.

C7A.023 maps to CMS-HCC V28 category 21, Lymphoma and Other Cancers. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for C7A.023. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

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