Villonodular synovitis (pigmented), other specified site

This code represents pigmented villonodular synovitis (PVNS) affecting an anatomical site other than the hip, knee, ankle/foot, shoulder, elbow, forearm, or hand. PVNS is a rare, benign, proliferative disorder of the synovial membrane, characterized by villous and nodular growth with hemosiderin deposition. It can lead to joint pain, swelling, and destructive arthropathy.

Use this code when documentation specifies PVNS occurring in a joint not explicitly covered by more specific M12.2 subcategories (e.g., temporomandibular joint, spine, sacroiliac joint). The physician's notes should clearly state the diagnosis of pigmented villonodular synovitis and identify the affected "other specified site."

• Ensure the documentation clearly identifies the specific joint affected to confirm it's not one with a more granular code.
• Do not use this code for unspecified sites; use M12.20 for PVNS of unspecified site.
• Code any associated joint effusion (M25.4x) or pain (M25.5x) separately, if documented.