C17.2 maps to CMS-HCC V28 20. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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 lookupC17.2

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of digestive organs (C15-C26)

C17.2

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

Malignant neoplasm of ileum

Cancer that develops in the ileum, which is the final and longest section of the small intestine.

Buddy Insight

Malignant neoplasm of the ileum affects the longest and most distal segment of the small intestine.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 20

Lung and Other Severe Cancers

Coefficient HCC 20: 1.136 (Community Non-Dual Aged (CNA))

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 009

HHS-HCC 009 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 9

Lung and Other Severe Cancers

Code-level coefficient reference

RXHCC

Mapped

HCC 22

Prostate, Breast, Bladder, an...

Code-level coefficient reference

Code Book Path

Official

C17Malignant neoplasm of small intestine C17.2Malignant neoplasm of ileum

Inclusion Terms

Official

No inclusion terms are included in this display for C17.2. Check the code and parent instructions in the Code Book.

Excludes 2

Official

gastrointestinal stromal tumors (C49.A-)Inherited from C15-C26

Related Codes

Official

C17.0Malignant neoplasm of duodenum C17.1Malignant neoplasm of jejunum C17.3Meckel's diverticulum, malignant C17.8Malignant neoplasm of overlapping sites of small intestine C17.9Malignant neoplasm of small intestine, unspecified

Includes

Official

No Includes notes are included in this display for C17.2. Check the code and parent instructions in the Code Book.

Excludes 1

Official

malignant neoplasm of ileocecal valve (C18.0)
Kaposi's sarcoma of gastrointestinal sites (C46.4)Inherited from C15-C26, C17
malignant carcinoid tumors of the small intestine (C7A.01)Inherited from C15-C26, C17

Code First

Official

No Code First sequencing instructions are included in this display for C17.2. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for C17.2. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for C17.2. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Confirmed ileal location as the primary malignant site

Histological type (neuroendocrine/carcinoid tumors are common in this location)

Any history of Crohn disease or other predisposing inflammatory conditions

Stage of disease including mesenteric lymph node involvement

MEAT Support

HCC Buddy guidance

Confirmed ileal location as the primary malignant site

Histological type (neuroendocrine/carcinoid tumors are common in this location)

Any history of Crohn disease or other predisposing inflammatory conditions

Stage of disease including mesenteric lymph node involvement

Audit Caution

HCC Buddy guidance

Using C17.2 for carcinoid tumors of the ileum when C7A.012 exists as a more specific code

Coding cecal cancer as ileal cancer when the tumor is at the ileocecal junction

Not recognizing Crohn disease-associated small bowel adenocarcinoma as a distinct entity requiring careful documentation

Failing to verify primary versus secondary malignancy in the ileum

Common Mistakes

HCC Buddy guidance

C17.1 — Jejunum: adjacent segment; boundary may be difficult to determine radiologically

C17.3 — Meckel diverticulum, malignant: if cancer arises in Meckel diverticulum specifically, use C17.3 rather than C17.2

C18.0 — Cecum: the terminal ileum connects to the cecum; ensure primary site is ileum not cecum

C7A.012 — Malignant carcinoid tumor of ileum: carcinoid tumors of the ileum have their own specific code

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 C17.2 an HCC code?

Yes. C17.2 (Malignant neoplasm of ileum) maps to HCC 20, Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.136. 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: C17.2 is billable and maps to V28 HCC 20, Lung and Other Severe Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: C17.2
Description: Malignant neoplasm of ileum
HCC (V28): HCC 20 — Lung and Other Severe Cancers
RAF reference coefficient: 1.136
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 20, Lung and Other Severe Cancers

1.136

ESRDHCC 9, Lung and Other Severe Cancers

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 C17.2 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C17.2

For C17.2, 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

C17.2 is the ICD-10-CM diagnosis code for malignant neoplasm of ileum. Cancer that develops in the ileum, which is the final and longest section of the small intestine. C17.2 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of digestive organs (c15-c26).

Under the CMS-HCC V28 risk adjustment model, C17.2 maps to Lung and Other Severe Cancers (HCC 20) with a source-labeled community, non-dual, aged reference coefficient of 1.136. 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.

Document whether this is primary ileal cancer or secondary involvement; ileal cancers are uncommon. For C17.2, 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 C17.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document whether this is primary ileal cancer or secondary involvement; ileal cancers are uncommon
•Note any association with Crohn's disease or other predisposing conditions if present

Clinical Significance

Malignant neoplasm of the ileum affects the longest and most distal segment of the small intestine. The ileum is a relatively common site for carcinoid (neuroendocrine) tumors and lymphoma compared to other small bowel segments. Ileal cancers may present with obstruction, intussusception, or bleeding, and patients with Crohn disease affecting the ileum have an increased risk of malignancy. Accurate coding ensures risk adjustment reflects the complex care these patients require.

Documentation Requirements

✓Confirmed ileal location as the primary malignant site
✓Histological type (neuroendocrine/carcinoid tumors are common in this location)
✓Any history of Crohn disease or other predisposing inflammatory conditions
✓Stage of disease including mesenteric lymph node involvement
✓Distinction from Meckel diverticulum malignancy (C17.3)

Excludes 1, Do NOT code together

malignant neoplasm of ileocecal valve (C18.0)

Commonly Confused Codes

•C17.1: Jejunum: adjacent segment; boundary may be difficult to determine radiologically
•C17.3: Meckel diverticulum, malignant: if cancer arises in Meckel diverticulum specifically, use C17.3 rather than C17.2
•C18.0: Cecum: the terminal ileum connects to the cecum; ensure primary site is ileum not cecum
•C7A.012: Malignant carcinoid tumor of ileum: carcinoid tumors of the ileum have their own specific code