2026 ICD-10-CM Diagnosis Code C40.31Malignant neoplasm of short bones of right lower limb
ICD-10-CM Codes›C00–D49›C40-C41›C40
- Billable — Valid for Submission
- Chronic Condition
C40.31 is a billable ICD-10-CM diagnosis code for malignant neoplasm of short bones of right lower 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bone cancer.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Neoplasm of bone of right foot
- Primary chondrosarcoma of bone of lower limb
- Primary chondrosarcoma of bone of right foot
- Primary chondrosarcoma of bone of right lower limb
- Primary Ewing sarcoma of bone of right foot
- Primary Ewing sarcoma of bone of right lower limb
- Primary malignant neoplasm of bone of right foot
- Primary malignant neoplasm of bone of right lower limb
- Primary osteosarcoma of bone of right foot
- Primary osteosarcoma of bone of right lower limb
- Sarcoma of bone of foot
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) › ankle | C40.3 | C79.51 | – | D16.3 | – | – |
| bone (periosteum) › astragalus | C40.3 | C79.51 | – | D16.3 | – | – |
| bone (periosteum) › calcaneus | C40.3 | C79.51 | – | D16.3 | – | – |
| bone (periosteum) › cuboid | C40.3 | C79.51 | – | D16.3 | – | – |
| bone (periosteum) › foot | C40.3 | C79.51 | – | D16.3 | – | – |
| bone (periosteum) › heel | C40.3 | C79.51 | – | D16.3 | – | – |
| bone (periosteum) › limb NEC › lower (long bones) › short bones | C40.3 | C79.51 | – | D16.3 | – | – |
| bone (periosteum) › metatarsus (any) | C40.3 | C79.51 | – | D16.3 | – | – |
| bone (periosteum) › navicular | C40.3 | C79.51 | – | – | – | – |
| bone (periosteum) › navicular › ankle | C40.3 | C79.51 | – | – | – | – |
| bone (periosteum) › phalanges | C40.3 | C79.51 | – | – | – | – |
| bone (periosteum) › phalanges › foot | C40.3 | C79.51 | – | – | – | – |
| bone (periosteum) › scaphoid › of ankle | C40.3 | C79.51 | – | – | – | – |
| bone (periosteum) › tarsus (any) | C40.3 | C79.51 | – | – | – | – |
| bone (periosteum) › toe (any) | C40.3 | C79.51 | – | – | – | – |
| metatarsus (any bone) | C40.3 | C79.51 | – | D16.3 | – | – |
| phalanges | C40.3 | C79.51 | – | D16.3 | – | – |
| phalanges › foot | C40.3 | C79.51 | – | D16.3 | – | – |
| tarsus (any bone) | C40.3 | C79.51 | – | D16.3 | – | – |
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 C40.31 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C40.31Overview
Is C40.31 (Malignant neoplasm of short bones of lower limb) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of short bones of right lower limb on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C40.31 group to?
When malignant neoplasm of short bones of right lower 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 C40.31?
Under the General Equivalence Mappings, malignant neoplasm of short bones of right lower limb converts to ICD-9-CM 170.8 (mal neo bones ankle/foot). 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.
