A 55-year-old Man with Painless Joint Swelling

Abstract

A 55-year-old man presented with swelling of left knee for the past one month. He also complained of episodes of joint locking. There was no history of pain, fever or trauma. Physical examination revealed localized increase in temperature of the skin, a large joint effusion, and decreased range of motion. His total leukocyte count was normal; ESR was raised to 48 mm in the first hour. Antero-posterior and lateral radiograph of the knee revealed large joint effusion with no bony abnormality. Subsequent magnetic resonance imaging (MRI) performed revealed joint effusion with lobulated enhancing synovial masses around the knee joint. The masses appeared low signal on T1 weighted (Fig. 1), T2-weighted and Proton density image (Fig. 2a). Blooming effect with marked loss of signal was seen on GRE-DESS image (Fig. 3). FNAC and joint aspiration was hemorrhagic. Synovial biopsy was performed and revealed villi and nodule with extensive hemosiderin deposition and abundant multinucleated giant cells. Figure 1 Sagittal T1-weighted MRI shows lobulated low signal synovial masses in knee joint and popliteal bursa with erosion of tibial condyle. Figures 2a and 2b Sagittal and axial proton density (PD) weighted MRI shows joint effusion with lobulated and frond-like heterogeneous hypointense lesion within the joint and bursa. Figure 3 Shows marked loss of signal with Blooming effect on GRE-DESS image. Questions What are the differential diagnoses and diagnosis? What is the management for this case and the role of MRI in it?' Answers The differential diagnoses of hypointense synovial masses on T2 weighted MRI are; pigmented villonodular synovitis (PVNS), synovial osteochondromatosis, hemophilic arthropathy, and amyloid deposition. The diagnosis was PVNS made by characteristic MRI and histopathological features. Complete synovectomy is the most common treatment; however, it is often not possible in large joints because of the complexity of the joint structure. Recurrence rates are high. Other treatment options include radiation therapy, pharmaceutical modulation of the disease, or a combination of these approaches. MRI has a very important role by demonstrating the characteristic finding and allows for the preoperative non-invasive diagnosis.