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Pigmented Villonodular Synovitis - Knee

Case Detail

Anatomy: Musculoskeletal
Joseph Junewick, MD FACR
Diagnostic Category: Neoplasia Benign
Created: over 8 years ago
Updated: over 8 years ago
Tags: MR
Modality/Study Types: PEDS
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15 year old male with intermittent pain, swelling, decrease range of motion of his right knee for 1 year.

Case Images


Pigmented Villonodular Synovitis – Knee


MR – Thickened, nodular and enhancing synoviium with mixed signal intra-articular mass adjacent to the posterior cruciate ligament.


Pigmented Villonodular Synovitis (PVNS) is a reactive inflammatory process of unknown etiology. The patient often presents with joint swelling, limited range of motion, pain, or sudden sharp pain if nodule is torsed. The affected patient demonstrates wide age range with a 1:2 male:female predominance of monoarticular disease. The monoarticular form most often affects the large joints with the knee being most common. Abnormal villous, nodular, or villonodular proliferated synovium is prone to hemorrhage. Rare polyarticular forms can be seen in children and are infrequently associated with other abnormalities such as vascular lesions, cherubism, and Noonan’s syndrome. Surgical resection is the current treatment strategy for PVNS with recurrence rates of 20-50%; recurrence is thought to be due to incomplete synovectomy. Radiographic features of PVNS include joint effusion, well defined subchondral cysts, and joint erosions; however, occasionally radiographs can also be normal. CT is nonspecific, but may show increased attenuation secondary to the hemosiderin deposition as well as enhancing synovium. MR imaging generally demonstrates a T1 low signal homogenous intraarticular mass with moderate to intense inhomogenous enhancement on postcontrast sequences. The typical T2 appearance is of a low signal intensity lesion, however variability in the appearance is attributed to hemosiderin, fibrous tissue, fat, and edema. Gradient echo images show “blooming” artifact secondary to hemosiderin. While this is not specific for PVNS, it helps to narrow the differential diagnosis.


Murphy, et al. Pigmented Villonodular Synovitis: A Radiology-Pathology Correlation. RadioGraphics; Sept 2008. 28. 1493-1518.


Jennifer Rollenhagen, MD

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