What is ICD-10 code D3A.020?

D3A.020 is the ICD-10-CM diagnosis code for Benign carcinoid tumor of the appendix. A benign neuroendocrine tumor located in the appendix, a small tube-shaped organ attached to the large intestine. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). D3A.020 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. D3A.020 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. D3A.020 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. D3A.020 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 D3A.020?

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. D3A.020 is a payment HCC under V28 (Bladder, Colorectal, and Other Cancers) but was not retained as a payment HCC under V24. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting D3A.020?

The appendix is a common site for carcinoid tumors; ensure appendix is clearly documented Distinguish from appendicitis or other appendiceal conditions Because D3A.020 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.

2026 ICD-10-CM D3A.020: Benign carcinoid tumor

ICD-10-CM Code View

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Code lookupD3A.020Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Benign neuroendocrine tumors (D3A)

D3A.020

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

Benign carcinoid tumor of the appendix

A benign neuroendocrine tumor located in the appendix, a small tube-shaped organ attached to the large intestine.

Buddy Insight

CMS-HCC V28

Mapped

HCC 22

Bladder, Colorectal, and Othe...

RAF 0.363

CMS-HCC V24

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

N/A

—

Not risk-adjusted for this model/period.

Not mapped

RXHCC

Mapped

HCC 22

Cancer, Other Specified Sites

RAF 0.124

Code Book Path

Official

D3A.0Benign carcinoid tumors

D3A.02Benign carcinoid tumors of the appendix, large intestine, and rectum

D3A.020Benign carcinoid tumor of the appendix

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for D3A.020 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for D3A.020 in this effective period.

Related Child Codes

Official

D3A.021Benign carcinoid tumor of the cecum

D3A.022Benign carcinoid tumor of the ascending colon

D3A.023Benign carcinoid tumor of the transverse colon

D3A.024Benign carcinoid tumor of the descending colon

D3A.025Benign carcinoid tumor of the sigmoid colon

Includes

Official

ICD-10-CM does not list Includes notes for D3A.020 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for D3A.020 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for D3A.020 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for D3A.020 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for D3A.020 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Surgical pathology from appendectomy documenting a well-differentiated neuroendocrine tumor with tumor size, depth of invasion, margin status, and Ki-67 proliferative index.

Document whether the tumor was discovered incidentally during appendectomy or was clinically suspected preoperatively.

For tumors greater than 1cm, note whether a completion right hemicolectomy was performed or recommended.

MEAT Support

HCC Buddy guidance

Surgical pathology from appendectomy documenting a well-differentiated neuroendocrine tumor with tumor size, depth of invasion, margin status, and Ki-67 proliferative index.

Document whether the tumor was discovered incidentally during appendectomy or was clinically suspected preoperatively.

For tumors greater than 1cm, note whether a completion right hemicolectomy was performed or recommended.

Audit Caution

HCC Buddy guidance

Tumor size is the most critical factor in determining management and coding

tumors under 1cm after simple appendectomy are almost always benign. Goblet cell carcinoid (now called goblet cell adenocarcinoma) is no longer classified as a carcinoid and requires different coding. Ensure the pathology distinguishes carcinoid from mucinous appendiceal neoplasms.

Common Mistakes

HCC Buddy guidance

C7A.020 (malignant carcinoid of appendix) is for tumors with malignant features (larger size, invasion, positive margins)

D3A.021 (cecum) is for tumors at the appendiceal-cecal junction or cecum proper

D37.3 (appendix, uncertain behavior) may apply when the benign vs. malignant distinction is unclear

C18.1 (malignant neoplasm of appendix) covers non-carcinoid appendiceal malignancies.

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 D3A.020 an HCC code?

Yes. D3A.020 (Benign carcinoid tumor of the appendix) maps to Bladder, Colorectal, and Other Cancers under the CMS-HCC V28 risk adjustment model, with a community non-dual aged RAF of 0.363. It is billable for payment year 2026.

Coder answer: D3A.020 is billable and maps to V28 HCC 22, Bladder, Colorectal, and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: D3A.020
Description: Benign carcinoid tumor of the appendix
HCC (V28): HCC 22 — Bladder, Colorectal, and Other Cancers
RAF: 0.363
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 22, Bladder, Colorectal, and Other Cancers

0.363

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 D3A.020 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for D3A.020

For D3A.020 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 D3A.020 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

D3A.020 is the ICD-10-CM diagnosis code for benign carcinoid tumor of the appendix. A benign neuroendocrine tumor located in the appendix, a small tube-shaped organ attached to the large intestine. D3A.020 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering benign neuroendocrine tumors (d3a).

Under the CMS-HCC V28 risk adjustment model, D3A.020 maps to Bladder, Colorectal, and Other Cancers (HCC 22) with a community, non-dual, aged base RAF weight of 0.363. D3A.020 was not retained as a payment HCC under the older V24 model, so V28 introduced or recategorized it during the 2024–2026 phase-in. 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 appendix is a common site for carcinoid tumors; ensure appendix is clearly documented. Because D3A.020 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 D3A.020 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•The appendix is a common site for carcinoid tumors; ensure appendix is clearly documented
•Distinguish from appendicitis or other appendiceal conditions

Clinical Significance

Benign carcinoid tumor of the appendix is the most common appendiceal neoplasm and the most common type of carcinoid tumor overall, frequently discovered incidentally during appendectomy for acute appendicitis. Most appendiceal carcinoids are small (less than 1cm), well-differentiated, and carry an excellent prognosis after simple appendectomy. Tumors greater than 2cm or with mesoappendiceal invasion may require right hemicolectomy.

Documentation Requirements

✓Surgical pathology from appendectomy documenting a well-differentiated neuroendocrine tumor with tumor size, depth of invasion, margin status, and Ki-67 proliferative index.
✓Document whether the tumor was discovered incidentally during appendectomy or was clinically suspected preoperatively.
✓For tumors greater than 1cm, note whether a completion right hemicolectomy was performed or recommended.

Commonly Confused Codes

•C7A.020 (malignant carcinoid of appendix) is for tumors with malignant features (larger size, invasion, positive margins)
•D3A.021 (cecum) is for tumors at the appendiceal-cecal junction or cecum proper
•D37.3 (appendix, uncertain behavior) may apply when the benign vs. malignant distinction is unclear
•C18.1 (malignant neoplasm of appendix) covers non-carcinoid appendiceal malignancies.