Villonodular synovitis (pigmented), unspecified hand

This code describes pigmented villonodular synovitis (PVNS), a rare, benign, proliferative disorder of the synovial membrane, affecting an unspecified hand. It is characterized by the overgrowth of the synovium, leading to villous, nodular, and diffuse lesions, often with hemosiderin deposition causing a brownish discoloration. This condition can cause pain, swelling, and limited joint mobility in the affected hand.

Use this code when documentation confirms a diagnosis of pigmented villonodular synovitis affecting any joint or tendon sheath within the hand, and the specific hand (left or right) is not documented. This diagnosis is typically made based on clinical presentation, imaging studies (MRI is often definitive), and confirmed by histopathological examination of synovial tissue.

• Ensure documentation specifies "pigmented" villonodular synovitis; otherwise, consider other synovitis codes.
• If the laterality (left or right hand) is documented, use the more specific code (M12.241 for right, M12.242 for left).
• This code is for the diagnosis itself; codes for surgical excision or other treatments would be reported separately.