2026 ICD-10-CM Diagnosis Code D41.21Neoplasm of uncertain behavior of right ureter

ICD-10-CM Codes›C00–D49›D37-D48›D41

ICD-10-CM D41.21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D41.21 is a billable ICD-10-CM diagnosis code for neoplasm of uncertain behavior of right ureter. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 656 through 658, 686 through 688. Coders also document this condition as bilateral neoplasm of uncertain behavior of ureters. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Neoplasms of unspecified nature or uncertain behavior.

Code Identity

ICD-10-CM Code
D41.21
Billable Status
Yes — Valid for Submission
Code Describes
Neoplasm of uncertain behavior of right ureter
Short Description
Neoplasm of uncertain behavior of right ureter
Same as the full description in the CMS dataset.
Parent Code
D41.2
Neoplasm of uncertain behavior of ureter

Code Classification

ChapterC00–D49Neoplasms
SectionD37-D48Neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes
CategoryD41Neoplasm of uncertain behavior of urinary organs
This CodeD41.21Neoplasm of uncertain behavior of right ureter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral neoplasm of uncertain behavior of ureters
  • Neoplasm of uncertain behavior of left ureter
  • Neoplasm of uncertain behavior of right ureter
  • Neoplasm of uncertain behavior of ureter

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NEO072
Neoplasms of unspecified nature or uncertain behavior
Default principal diagnosis: inpatient Yes · outpatient Yes

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
ureter, ureteralC66.C79.19D09.19D30.2D41.2D49.59

Patient EducationClinical

Ureteral Disorders

Your kidneys make urine by filtering wastes and extra water from your blood. The urine travels from the kidneys to the bladder in two thin tubes called ureters.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert D41.21 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
236.91 Unc behav neo kidney
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About D41.21Overview

Is D41.21 (Neoplasm of uncertain behavior of ureter) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report neoplasm of uncertain behavior of right ureter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does D41.21 group to?

When neoplasm of uncertain behavior of right ureter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 656, 657, 658, 686, 687, 688, with relative weights from 0.7903 to 3.1838 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of D41.21?

Under the General Equivalence Mappings, neoplasm of uncertain behavior of right ureter converts to ICD-9-CM 236.91 (unc behav neo kidney). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.