2026 ICD-10-CM Diagnosis Code C40.91Malignant neoplasm of unspecified bones and articular cartilage of right limb

ICD-10-CM Codes›C00–D49›C40-C41›C40

ICD-10-CM C40.91
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C40.91 is a billable ICD-10-CM diagnosis code for malignant neoplasm of unspecified bones and articular cartilage of right limb. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 542 through 544. Coders also document this condition as ewing sarcoma of bone structure of upper limb. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bone cancer.

Code Identity

ICD-10-CM Code
C40.91
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of unspecified bones and articular cartilage of right limb
Short Description
Malig neoplasm of unsp bones and artic cartlg of right limb
Parent Code
C40.9
Malignant neoplasm of unspecified bones and articular cartilage of limb

Code Classification

ChapterC00–D49Neoplasms
SectionC40-C41Malignant neoplasms of bone and articular cartilage
CategoryC40Malignant neoplasm of bone and articular cartilage of limbs
This CodeC40.91Malignant neoplasm of unspecified bones and articular cartilage of right limb

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Ewing sarcoma of bone structure of upper limb
  • Neoplasm of bone of right hand
  • Primary Ewing sarcoma of bone of hand
  • Primary Ewing sarcoma of bone of right hand
  • Primary Ewing sarcoma of bone of right upper limb
  • Primary Ewing sarcoma of bone structure of upper limb
  • Primary malignant neoplasm of bone of right hand

Clinical ClassificationClinical

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

CCSR NEO023
Bone cancer
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.
bone (periosteum) › limb NECC40.9C79.51–D16.9––

Patient EducationClinical

Bone Cancer

Cancer that starts in a bone is uncommon. Cancer that has spread to the bone from another part of the body is more common.

Read the full article at MedlinePlus

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

Convert C40.91 to ICD-9-CMHistory

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

ICD-9-CM
170.9 Malig neopl bone NOS
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 C40.91Overview

Is C40.91 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of unspecified bones and articular cartilage of right limb on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C40.91 group to?

When malignant neoplasm of unspecified bones and articular cartilage of right limb is the principal diagnosis on an inpatient stay, it groups to MS-DRG 542, 543, 544, with relative weights from 0.7546 to 1.7665 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C40.91?

Under the General Equivalence Mappings, malignant neoplasm of unspecified bones and articular cartilage of right limb converts to ICD-9-CM 170.9 (malig neopl bone NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.