ICD-10 Code C40 – Malignant neoplasm of bone and articular cartilage of limbs (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C40 – Malignant neoplasm of bone and articular cartilage of limbs
What it is
C40 identifies a malignant tumor arising in the bones or articular cartilage of the upper or lower limbs. Use it when the documentation states a primary cancer in an arm or leg bone.
Clinical signs
Typical findings include persistent limb pain, swelling, a palpable mass, or pathologic fracture. Imaging and pathology usually confirm a malignant bone or cartilage neoplasm; clinical features vary, so refer to documentation.
When to use this code
Use C40 when the provider documents a primary malignant neoplasm of a limb bone or articular cartilage, such as the femur, tibia, humerus, or related joint cartilage. Code the site as documented and confirm laterality or specific subsite if available.
Choose this code for confirmed primary bone malignancy in an extremity, including cases described as sarcoma of bone or cartilage in a limb. If the record is unclear about the exact site or primary nature, check documentation.
Do not use for
Do not use C40 for metastatic bone disease, benign bone tumors, or malignancies of soft tissue. Do not substitute it for unspecified bone cancer when the limb site is not documented.
Coding tip
Verify whether the tumor is primary and located in a limb bone or articular cartilage before assigning C40.