ICD-10 Code C40.91 – Malignant neoplasm of unspecified bones and articular cartilage of right limb (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C40.91 – Malignant neoplasm of unspecified bones and articular cartilage of right limb
What it is
This code identifies a malignant tumor arising in the bones or articular cartilage of the right limb when the exact site is not further specified. Use it when documentation confirms a primary bone or cartilage cancer in the right arm or leg.
Clinical signs
Typical findings include localized pain, swelling, or a palpable mass in the affected limb. Imaging or biopsy usually supports the diagnosis; clinical features vary, so refer to documentation.
When to use this code
Use C40.91 when the provider documents a malignant neoplasm of unspecified bones or articular cartilage in the right limb and no more specific bone site is named. It may also apply when pathology or imaging confirms the diagnosis, but the record does not identify the exact bone. If the site is later clarified, you should code the more specific location.
Do not use for
Do not use this code for benign bone tumors, metastatic disease to bone, or cancers in the left limb or an unspecified limb. Check documentation if the record names a different primary site.
Coding tip
Verify that the lesion is primary to bone or articular cartilage and that the right limb is documented before assigning C40.91.