Saudi Journal of Medicine and Medical Sciences

: 2018  |  Volume : 6  |  Issue : 2  |  Page : 121--124

A hypertrophic mass-like synovium

Mona Al Muhaish 
 Department of Radiology, King Fahd Hospital of the University, Al Khobar, Saudi Arabia

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Al Muhaish M. A hypertrophic mass-like synovium.Saudi J Med Med Sci 2018;6:121-124

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Al Muhaish M. A hypertrophic mass-like synovium. Saudi J Med Med Sci [serial online] 2018 [cited 2021 Apr 17 ];6:121-124
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A 22-year-old female presented to an orthopedic surgeon with a history of right knee pain and swelling for the past few months. The patient had no history of trauma and fever. Physical examination revealed moderate knee joint effusion with a limited range of motion. For further evaluation, the patient underwent radiography and magnetic resonance imaging (MRI) [Figure 1].{Figure 1}


What are the findings and diagnosis?

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The lateral radiograph of the right knee shows swelling at the posterior joint recess and, to a lesser extent, in the suprapatellar region. No calcification is observed.

Extensive lobulated mass-like synovial proliferation is observed with low-signal intensity on T1 and susceptibility artifact (blooming) on gradient echo sequence. No erosions or joint space narrowing is observed. The diagnosis is pigmented villonodular synovitis (PVNS).


PVNS is a rare, benign, proliferative lesion of uncertain etiology that affects synovium, bursae and tendon sheaths. Commonly, PVNS is a monoarticular process and occurs either as a localized or diffuse form.[1],[2] It affects the knee in 80% of the cases, but can also affect the hip, ankle, shoulder and elbow. Although PVNS can occur at any age, it mostly occurs in adults aged 20–50 years, with no gender predilection.[2]

Patients with PVNS often have a slow progressive pain along with swelling and a decrease in range of motion. Another commonly observed finding is history of a recurrent, bloody joint effusion.[2] In the knee, PVNS typically manifests as a nonspecific joint effusion. Bone erosions are observed in 25% of these cases; such a low rate is because of the capacious joint space.[2]

An MRI, owing to its very specific imaging features, can help differentiate PVNS from other synovial processes, and thus is the most widely used method for diagnosing PVNS. MRI examination would generally reveal a synovial-based mass affecting the entire or most of the joint with low-signal intensity on T1- and T2-weighted pulse sequences. Another signal characteristic is the presence of the magnetic susceptibility artifact in the affected joint space on gradient echo images.[1],[2] The differential diagnosis of PVNS includes hemophilia-related arthropathy, amyloid arthropathy and synovial chondromatosis.

In terms of management, surgical excision is considered as the optimal treatment. The success of surgical excision depends on complete resection with clear margins. However, in the extensive diffuse form of the disease, complete resection is rarely possible, and thus surgery is carried out primary for debulking before initiating radiation (with external beam and radiosynoviorthesis) or medication therapy (with immunomodulating agents such as infliximab). The recurrence rates for localized and diffuse forms of PVNS have been reported to vary from 0% to 44% and from 8% to 56%, respectively. Notably, higher recurrence rates have been reported in cases where complete synovectomy could not be performed.[3],[4]

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Conflicts of interest

There are no conflicts of interest.


1Kempson RL, Fletcher CD, Evans HL, Hendrickson MR, Sibley RK. Synovial tumors. In: Atlas of Tumor Pathology: Rumors of the Soft Tissues. 3rd Ser., Vol. 138. Washington, DC.: Armed Forces Institute of Pathology; 2001. p. 387-94.
2Murphey MD, Rhee JH, Lewis RB, Fanburg-Smith JC, Flemming DJ, Walker EA, et al. Pigmented villonodular synovitis: Radiologic-pathologic correlation. Radiographics 2008;28:1493-518.
3Ottaviani S, Ayral X, Dougados M, Gossec L. Pigmented villonodular synovitis: A retrospective single-center study of 122 cases and review of the literature. Semin Arthritis Rheum 2011;40:539-46.
4Klammer G, Betz M, Delaloye B, Farshad M, Peter KP. Bilateral diffuse pigmented villonodular synovitis of the knee. J Knee Surg 2013;26 Suppl 1:S67-71.