C66.9 ICD-10-CM Code: Malignant neoplasm of unspecified ureter
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Inpatient Payment Groups (MS-DRG)
MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0 (FY2026), Appendix B.
- MS-DRG 656 — KIDNEY AND URETER PROCEDURES FOR NEOPLASM WITH MCC (MDC 11)
- MS-DRG 657 — KIDNEY AND URETER PROCEDURES FOR NEOPLASM WITH CC (MDC 11)
- MS-DRG 658 — KIDNEY AND URETER PROCEDURES FOR NEOPLASM WITHOUT CC/MCC (MDC 11)
- MS-DRG 686 — KIDNEY AND URINARY TRACT NEOPLASMS WITH MCC (MDC 11)
- MS-DRG 687 — KIDNEY AND URINARY TRACT NEOPLASMS WITH CC (MDC 11)
- MS-DRG 688 — KIDNEY AND URINARY TRACT NEOPLASMS WITHOUT CC/MCC (MDC 11)
A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.
Risk Adjustment (CMS-HCC)
Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.
- HCC 22 — Bladder, Colorectal, and Other Cancers (supersedes HCC 23)
Other models: CMS-HCC V22 HCC 11 · RxHCC V08 HCC 22
Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.
Code Set: Valid FY2026 and FY2027. FY2026 took effect October 1, 2025.
Official Registry Overview & Definition
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for C66.9 in the official ICD-10-CM tabular list.
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- malignant neoplasm of ureteric orifice of bladder (C67.6)
Nearest Codes in This Family
Official ICD-10-CM classifications closest to C66.9 in its code family, with their registry titles.
Neoplasm Table Sites (1)
Anatomical sites from the official ICD-10-CM Table of Neoplasms that map to this code, with the matching behavior column.
- Neoplasm, neoplastic, ureter, ureteral — Malignant, Primary