2026 ICD-10-CM Diagnosis Code C41.9Malignant neoplasm of bone and articular cartilage, unspecified

ICD-10-CM Codes›C00–D49›C40-C41›C41

ICD-10-CM C41.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C41.9 is a billable ICD-10-CM diagnosis code for malignant neoplasm of bone and articular cartilage, unspecified. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bone cancer.

Code Identity

ICD-10-CM Code
C41.9
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of bone and articular cartilage, unspecified
Short Description
Malignant neoplasm of bone and articular cartilage, unsp
Parent Code
C41
Malignant neoplasm of bone and articular cartilage of other and unspecified sites

Code Classification

ChapterC00–D49Neoplasms
SectionC40-C41Malignant neoplasms of bone and articular cartilage
CategoryC41Malignant neoplasm of bone and articular cartilage of other and unspecified sites
This CodeC41.9Malignant neoplasm of bone and articular cartilage, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Carcinoma of bone, connective tissue, skin and breast
  • Chondrosarcoma
  • Chondrosarcoma of bone
  • Clear cell chondrosarcoma
  • Conventional osteosarcoma
  • Dedifferentiated chondrosarcoma
  • Diaphyseal medullary stenosis with bone malignancy
  • Disseminated Langerhans cell histiocytosis of bone
  • Ewing's sarcoma of bone
  • Extraskeletal mesenchymal chondrosarcoma
  • Extraskeletal myxoid chondrosarcoma
  • High-grade surface osteosarcoma
  • Langerhans cell histiocytosis, disseminated
  • Large cell Ewing sarcoma of bone
  • Local recurrence of malignant neoplasm of bone
  • Low-grade central osteosarcoma
  • Macrocytosis - no anemia
  • Malignant giant cell tumor of bone
  • Malignant neoplasm of articular cartilage
  • Malignant neoplasm of bone
  • Malignant neoplasm of bone, connective tissue, skin and breast
  • Malignant neoplasm of skeletal system
  • Malignant neoplasm of vertebra
  • Mesenchymal chondrosarcoma
  • Metastatic extraskeletal osteosarcoma
  • Metastatic malignant neoplasm to articular cartilage
  • Metastatic malignant neoplasm to clavicle
  • Metastatic malignant neoplasm to long bone of upper limb
  • Metastatic malignant neoplasm to rib
  • Metastatic malignant neoplasm to sternum
  • Metastatic malignant neoplasm to vertebral column
  • Metastatic osteosarcoma to articular cartilage of clavicle
  • Metastatic osteosarcoma to articular cartilage of rib
  • Metastatic osteosarcoma to articular cartilage of sternum
  • Metastatic osteosarcoma to articular cartilage of vertebra
  • Metastatic osteosarcoma to bone
  • Metastatic osteosarcoma to bone of clavicle
  • Metastatic osteosarcoma to bone of head
  • Metastatic osteosarcoma to bone of rib
  • Metastatic osteosarcoma to bone of sternum
  • Metastatic osteosarcoma to bone of vertebra
  • Non-anemic red cell disorder
  • Osteosarcoma
  • Osteosarcoma of articular cartilage of clavicle
  • Osteosarcoma of articular cartilage of rib
  • Osteosarcoma of articular cartilage of sternum
  • Osteosarcoma of articular cartilage of vertebra
  • Osteosarcoma of bone
  • Osteosarcoma of bone of clavicle
  • Osteosarcoma of bone of head
  • Osteosarcoma of bone of rib
  • Osteosarcoma of bone of upper limb
  • Osteosarcoma of bone of vertebra
  • Osteosarcoma of sternum
  • Osteosarcoma, limb anomalies, erythroid macrocytosis syndrome
  • Overlapping malignant neoplasm of bone and articular cartilage
  • Parosteal osteosarcoma
  • Periosteal chondrosarcoma
  • Periosteal osteosarcoma
  • Primary chondrosarcoma of articular cartilage
  • Primary chondrosarcoma of bone
  • Primary Ewing sarcoma of bone
  • Primary large cell Ewing sarcoma of bone
  • Primary malignant neoplasm of articular cartilage
  • Primary malignant neoplasm of bone
  • Primary osteosarcoma
  • Primary osteosarcoma of bone
  • Sarcoma of bone
  • Sarcoma of bone and connective tissue
  • Sarcoma of clavicle
  • Sarcoma of rib
  • Sarcoma of sternum
  • Sarcoma of vertebra
  • Small cell osteosarcoma
  • Telangiectatic osteosarcoma

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Osteitis
      • deformans
        • in (due to)
          • malignant neoplasm of bone (see also, Neoplasm, malignant, by site)

Clinical ClassificationClinical

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

CCSR NEO023
Bone cancer
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Osteosarcoma

    a sarcoma originating in bone-forming cells, affecting the ends of long bones. it is the most common and most malignant of sarcomas of the bones, and occurs chiefly among 10- to 25-year-old youths. (from stedman, 25th ed)

  • Osteosarcoma, Juxtacortical

    a form of osteogenic sarcoma of relatively low malignancy, probably arising from the periosteum and initially involving cortical bone and adjacent connective tissue. it occurs in middle-aged as well as young adults and most commonly affects the lower part of the femoral shaft. (stedman, 25th ed)

  • Chondrosarcoma

    a slowly growing malignant neoplasm derived from cartilage cells, occurring most frequently in pelvic bones or near the ends of long bones, in middle-aged and old people. most chondrosarcomas arise de novo, but some may develop in a preexisting benign cartilaginous lesion or in patients with enchondromatosis. (stedman, 25th ed)

  • Chondrosarcoma, Clear Cell

    a chondrosarcoma of adolescence to old age of the proximal epiphyses of long bones. it has variably clear cytoplasm of the mostly neoplastic chondrocytes with little intervening matrix.

  • Chondrosarcoma, Mesenchymal

    a rare aggressive variant of chondrosarcoma, characterized by a biphasic histologic pattern of small compact cells intermixed with islands of cartilaginous matrix. mesenchymal chondrosarcomas have a predilection for flat bones; long tubular bones are rarely affected. they tend to occur in the younger age group and are highly metastatic. (devita jr et al., cancer: principles & practice of oncology, 3d ed, p1456)

  • Enchondromatosis

    benign growths of cartilage in the metaphyses of several bones.

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)C41.9C79.51–D16.9D48.0D49.2
bone (periosteum) › cartilage NECC41.9C79.51–D16.9D48.0D49.2
bone (periosteum) › cuneiformC41.9C79.51–D16.9D48.0D49.2
cartilage (articular) (joint) NEC [See Also: Neoplasm, bone]C41.9C79.51–D16.9D48.0D49.2
joint NEC [See Also: Neoplasm, bone]C41.9C79.51–D16.9D48.0D49.2
skeleton, skeletal NECC41.9C79.51–D16.9D48.0D49.2

Patient EducationClinical

Cancer

Cancer is not just one disease but many diseases. Cancer begins in your cells, which are the building blocks of your body. Usually, your body forms new cells as needed, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don't need them, and old cells don't die when they should.

The full article covers:

  • What is cancer?
  • What are the types of cancer?
  • How does cancer develop?
  • What are the symptoms of cancer?
  • How is cancer diagnosed?
  • What are the treatments for cancer?
  • Can cancer be prevented?

Read the full article at MedlinePlus

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

Convert C41.9 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 C41.9Overview

Is C41.9 a billable code?

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

What MS-DRG does C41.9 group to?

When malignant neoplasm of bone and articular cartilage, unspecified 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 C41.9?

Under the General Equivalence Mappings, malignant neoplasm of bone and articular cartilage, unspecified 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.