ICD-10 C16.4
Billable / Specific HCC v28: 9 CCMalignant neoplasm of pylorus
About ICD-10-CM C16.4
ICD-10-CM code C16.4 represents Malignant neoplasm of pylorus. This is a billable/specific code in the Neoplasms chapter (block C16). The 2026 edition of ICD-10-CM C16.4 became effective on October 1, 2025.
Coding Tips for C16.4
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
C16.4 is a CMS-HCC v28 risk-adjustment code (category 9). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
C16.4 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under C16.4. Per CMS ICD-10-CM Tabular 2026.
- Malignant neoplasm of prepylorus
- Malignant neoplasm of pyloric canal
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, CC
codes Malignant neoplasm of pylorus. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for C16.4
Local Coverage Determinations (LCDs) from CMS MACs that list C16.4 as a covered diagnosis.
Showing top 10 of 990 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing C16.4.
5 Medicare
CPT Codes Commonly Billed with C16.4
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 43244 CMS LCD: Billing and Coding: Diagnostic and Therapeutic Esophagogastroduodenoscopy CMS LCD
- 43251 CMS LCD: Billing and Coding: Diagnostic and Therapeutic Esophagogastroduodenoscopy CMS LCD
- 43241 CMS LCD: Billing and Coding: Diagnostic and Therapeutic Esophagogastroduodenoscopy CMS LCD
- 43243 CMS LCD: Billing and Coding: Diagnostic and Therapeutic Esophagogastroduodenoscopy CMS LCD
- 43270 CMS LCD: Billing and Coding: Diagnostic and Therapeutic Esophagogastroduodenoscopy CMS LCD
- 43253 CMS LCD: Billing and Coding: Diagnostic and Therapeutic Esophagogastroduodenoscopy CMS LCD
- 43246 CMS LCD: Billing and Coding: Diagnostic and Therapeutic Esophagogastroduodenoscopy CMS LCD
- 43233 CMS LCD: Billing and Coding: Diagnostic and Therapeutic Esophagogastroduodenoscopy CMS LCD
- 43237 CMS LCD: Billing and Coding: Diagnostic and Therapeutic Esophagogastroduodenoscopy CMS LCD
- 43248 CMS LCD: Billing and Coding: Diagnostic and Therapeutic Esophagogastroduodenoscopy CMS LCD
Convert C16.4 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| C16.4 | 1511 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To C16.4
Other codes in section C15-C26 (Malignant neoplasms of digestive organs).
ICD-10 C16.4, Billing FAQ
Is ICD-10 code C16.4 billable? +
Yes, C16.4 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to C16.4? +
ICD-10 C16.4 includes: Malignant neoplasm of prepylorus; Malignant neoplasm of pyloric canal.
Does C16.4 affect Medicare Advantage HCC risk adjustment? +
Yes. C16.4 maps to CMS-HCC v28 category 9. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is C16.4 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with C16.4? +
Procedures frequently paired with C16.4 include: 43244, 43251, 43241, 43243, 43270.
What ICD-9 codes does C16.4 map to? +
Per CMS GEMs, C16.4 maps to ICD-9 codes: 1511. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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