C17.1
BillableMalignant neoplasm of jejunum
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C17.1 an HCC code?
Yes. C17.1 maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Lung and Other Severe Cancers under V24).
HCC Category Mapping
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 C17.1
For C17.1 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 C17.1 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C17.1 is the ICD-10-CM diagnosis code for malignant neoplasm of jejunum. Cancer that develops in the jejunum, which is the middle section of the small intestine. C17.1 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, C17.1 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 0.000. Under the older V24 model, C17.1 mapped to the same category but with a base RAF weight of 0.973 — V28 recalibrated weights across the entire model. 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.
Small intestine cancers are rare; ensure histological type is documented (adenocarcinoma, sarcoma, lymphoma, etc.). Because C17.1 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 C17.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Small intestine cancers are rare; ensure histological type is documented (adenocarcinoma, sarcoma, lymphoma, etc.)
- •Verify this is not a metastatic lesion from another primary site
Clinical Significance
Malignant neoplasm of the jejunum is rare, representing a small fraction of all gastrointestinal cancers. The jejunum is the middle segment of the small intestine, and cancers here are often diagnosed late due to vague, nonspecific symptoms. Despite their rarity, jejunal cancers carry significant morbidity and require surgical resection, making accurate coding important for reflecting the true resource needs of these patients.
Documentation Requirements
- ✓Documentation confirming jejunum as the primary tumor location
- ✓Histological type (adenocarcinoma, sarcoma, lymphoma, neuroendocrine)
- ✓Confirmation of primary versus metastatic disease
- ✓Any predisposing conditions (Crohn disease, celiac disease, Peutz-Jeghers syndrome)
- ✓Stage of disease and surgical findings
Commonly Confused Codes
- •C17.0 — Duodenum: the duodenum is the first segment; the jejunum begins at the ligament of Treitz
- •C17.2 — Ileum: the ileum is the distal segment; boundaries between jejunum and ileum may be unclear on imaging
- •C17.9 — Small intestine, unspecified: use C17.1 when jejunum is specifically documented
- •C83.- — Non-Hodgkin lymphoma: primary intestinal lymphoma may present in the jejunum but is coded to lymphoma categories