Disclosures: Lok Valentas, MD: No financial relationships or conflicts of interest

Case Diagnosis: A 32-year-old man with recurrent anterior left knee pain due to pigmented villonodular synovitis (PVNS)

Case Description: Patient with a history of left knee pain due to localized pigmented villonodular synovitis (PVNS) in the suprapatellar bursa, confirmed by pathology and resolved after arthroscopic partial synovectomy 4 years ago, returns with 6 months of recurrent knee pain. Pain is described as anterior, aching, and aggravated with activity. He denied numbness, tingling, mechanical symptoms, and inability to bear weight. Physical examination revealed quadriceps tendon and fat pad tenderness without effusion or mechanical symptoms. Given his history, magnetic resonance imaging (MRI) was obtained which showed resolution of his previous localized PVNS in the suprapatellar bursa, with a new occurrence in the anterior joint recess at the level of the intercondylar notch.

Setting: Outpatient sports medicine clinicAssessment/

Results: Patient was referred to orthopedic surgery with plan for left knee arthroscopy.

Discussion: Proliferative villonodular synovitis (PVNS) is an infrequent cause of anterior knee pain that typically affects middle-aged patients. It is characterized as a benign, though with rare potential for malignant transformation, proliferation of synovium that can affect tendon sheaths, joints, and bursae. Magnetic resonance imaging is the preferred diagnostic imaging modality, and displays a low signal lobulated mass on T1 and T2 weighted images and “blooming” artifact on gradient echo due to the presence of hemosiderin. PVNS can be classified into localized and diffuse forms. Localized PVNS is less invasive with a lower recurrence rate, and can typically be treated with partial synovectomy. This is in contrast to diffuse PVNS which has a higher recurrence rate and more likely to require total synovectomy.

Conclusion: Proliferative villonodular synovitis of the knee can mimic many more common etiologies of knee pain. One must keep a broad differential in mind, especially in a patient with a previous history of PVNS.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/localized-pigmented-villonodular-synovitis-as-a-cause-of-knee-pain-a-case-report/