2027 ICD-10-CM Diagnosis Code C41.9Malignant neoplasm of bone and articular cartilage, unspecified
ICD-10-CM Codes›C00–D49›C40-C41›C41
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 21
- Chronic Condition
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 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 542 through 544. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 25 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bone cancer.
For Medicare Advantage risk adjustment, C41.9 maps to CMS-HCC Category 21 (Lymphoma and Other Cancers) under the V28 model, adding a risk factor of about 0.671 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C41.9 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
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
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to C41.9: its own notes plus those printed at C41, block C40-C41, and Chapter 2. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- malignant neoplasm of cartilage (articular) (joint)
- malignant neoplasm of periosteum
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
Notes
General instructions on how these codes are used.
- Functional activity
- All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
- Morphology [Histology]
- Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
- Primary malignant neoplasms overlapping site boundaries
- A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
- Malignant neoplasm of ectopic tissue
- Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name C41.9, its category, or a range that includes it.
Applicable To 1
These notes mention C41.9.
- Z85.83 Personal history of malignant neoplasm of bone and soft tissue
Excludes1 1
These codes carry an Excludes1 note naming C41.9: they are not reported together with it, unless the two conditions are unrelated.
- C49 Malignant neoplasm of other connective and soft tissue
Code First 1
These codes say to code first a condition named in the note, and C41.9 is one of the conditions named.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Osteitis See Also: Osteomyelitis;
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Table of NeoplasmsClinical
Anatomical sites in the Table of Neoplasms that reference this code family.
| Site | Malig. Primary | Malig. Secondary | Ca in situ | Benign | Uncertain | Unspec. |
|---|---|---|---|---|---|---|
| bone (periosteum) | C41.9 | C79.51 | – | D16.9 | D48.0 | D49.2 |
| bone (periosteum) › cartilage NEC | C41.9 | C79.51 | – | D16.9 | D48.0 | D49.2 |
| bone (periosteum) › cuneiform | C41.9 | C79.51 | – | D16.9 | D48.0 | D49.2 |
| cartilage (articular) (joint) NEC [See Also: Neoplasm, bone] | C41.9 | C79.51 | – | D16.9 | D48.0 | D49.2 |
| joint NEC [See Also: Neoplasm, bone] | C41.9 | C79.51 | – | D16.9 | D48.0 | D49.2 |
| skeleton, skeletal NEC | C41.9 | C79.51 | – | D16.9 | D48.0 | D49.2 |
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Convert C41.9 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C41.9Overview
What is the ICD-10 code for malignant neoplasm of bone and articular cartilage, unspecified?
The ICD-10-CM code for malignant neoplasm of bone and articular cartilage, unspecified is C41.9 (sometimes written as C419). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
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, 2026 through September 30, 2027.
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 543, 544, 542, with relative weights from 0.7404 to 1.7208 depending on complications. Higher weights mean higher Medicare reimbursement.
Is C41.9 a CC or MCC?
CMS lists C41.9 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 25 closely related codes in its exclusion list.
Can C41.9 be reported with a code from C40?
Not as a rule. The Excludes1 note at C41, which applies to C41.9, lists "malignant neoplasm of bones of limbs (C40.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What HCC is C41.9?
C41.9 (malignant neoplasm of bone and articular cartilage, unspecified) maps to CMS-HCC Category 21 (Lymphoma and Other Cancers), commonly written as HCC 21, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 10 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 22.
Does C41.9 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C41.9 adds a risk adjustment factor of about 0.671 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.493 to 0.739 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, and HCC 20) supersedes it when both are reported. See the full factor table on the HCC 21 category page.
