Pigmented Villonodular Synovitis
Last updated: November 4, 2014
ICD-9 Code: 727.02
Definition: Pigmented villonodular synovitis is a benign tenosynovial or articular proliferative synovial neoplasm, frequently containing hemosiderinladen cells.
Etiology: A nonmalignant tumor of unknown etiology. It may be preceded by trauma in a minority of cases. Malignant transformation is rare.
Demographics: The diffuse articular form is rare, with equal gender distribution. A localized tenosynovial form is more common, with a slight female predominance. Peak onset is during the third to fourth decade.
Cardinal Findings: Diffuse pigmented villonodular synovitis often presents insidiously as monarthritis of a lower extremity, especially the knee. Long- standing discomfort and swelling may be confused with chronic inflammatory arthropathies. Localized tenosynovial pigmented villonodular synovitis occurs as a painless nodular lesion, often next to a finger joint, and may be confused with a giant cell tumor of the tendon sheath. Recurrence is common.
Diagnostic Testing: Routine studies are normal. Synovial fluid is frankly bloody or xanthochromic. Plain radiographs of diffuse disease show a soft tissue mass often associated with effusion, bone erosions, or cartilage loss. T2-weighted MRI shows a diminished signal in areas of pigmented villonodular synovitis owing to increased hemosiderin (iron) content. Definitive diagnosis may be established by synovial biopsy or at the time of surgical resection. Diffuse pigmented villonodular synovitis has coarse villi and is locally invasive to the bone. Grossly, the diffuse lesion is yellow to dark brown.
Keys to Diagnosis: Bloody synovial fluid and characteristic MRI appearance suggests pigmented villonodular synovitis. It needs to be distinguished from soft tissue tumors, giant cell tumor, and osteochondromatosis.
Therapy: Surgical resection is used in most cases; 30% to 50% recur. External and intraarticular irradiation has met with varying success.
Davidson A, Bentley G. Pigmented villonodular synovitis following arthroscopic laser surgery of the knee. Arthroscopy 2001;17:412–414. PMID:11288016