ICD-10 Code C40.3 – Malignant neoplasm of short bones of lower limb (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C40.3 – Malignant neoplasm of short bones of lower limb
What it is
C40.3 identifies a malignant bone tumor arising in the short bones of the lower limb, such as the tarsal or metatarsal bones. Use it when documentation specifies a primary cancer in these bones.
Clinical signs
Typical findings include persistent localized pain, swelling, or a palpable mass in the affected foot or lower-limb bone. Imaging and pathology confirm malignancy; clinical features vary; refer to documentation.
When to use this code
Use C40.3 when the provider documents a primary malignant neoplasm of a short bone in the lower limb. It may also apply when the site is clearly identified in the foot bones and the tumor is malignant. If the record only says “bone cancer” without site, check documentation.
Do not use for
Do not use this code for benign bone tumors, metastatic disease to bone, or malignancies in long bones of the leg. If the bone site is unspecified or the diagnosis is uncertain, check documentation.
Coding tip
Confirm that the documented site is a short bone of the lower limb before assigning C40.3.