ICD-10 Code C40.31 – Malignant neoplasm of short bones of right lower limb (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C40.31 – Malignant neoplasm of short bones of right lower limb
What it is
This code identifies a malignant tumor arising in the short bones of the right lower limb, such as the tarsal or metatarsal bones. Use it when the documentation specifies primary cancer in that anatomic site.
Clinical signs
Typical findings include localized pain, swelling, or a palpable mass in the right foot or lower limb bones. Imaging and pathology usually confirm the diagnosis; clinical features vary, so refer to documentation.
When to use this code
Use C40.31 when the provider documents a primary malignant neoplasm in the short bones of the right lower limb. Code it from operative, pathology, or oncology notes that clearly identify the site and laterality. If the record is unclear, check documentation before assigning the code.
Do not use for
Do not use this code for benign bone tumors, metastatic disease to the bone, or malignancies in the left lower limb. If the site is not specifically the short bones of the right lower limb, check documentation.
Coding tip
Confirm both laterality and bone group in the note before coding; the right-side designation is essential.