Synovial lipomatosis: A rare cause of knee pain in an adolescent female

Figure 1 Right knee magnetic resonance imaging demonstrating effusion in the suprapatellar bursa and hypertrophic synovium with leaf-like projections of tissue which has the same signal intensity as fat. A: Coronal proton density (PD); B: Coronal PD fat saturation; C: Sagittal PD; D: Axial T2 fat saturation.

Figure 2 Left knee magnetic resonance imaging demonstrating effusion in the suprapatellar bursa and hypertrophic synovium with leaf-like projections of tissue which has the same signal intensity as fat. A: Coronal proton density (PD); B: coronal PD fat saturation; C: Sagittal PD; D: Axial T2 fat saturation.

Figure 3 Descriptions of benign synovial tissue and fragments of adipose present beneath the synovial surface. A: Villous and nodular fatty projections common in synovial lipomatosis (Hematoxylin/eosin, 20 x); B: Synovial tissue with papillary architecture replaced by mature adipocytes with infiltration of lymphocytes and plasma cells. (Hematoxylin/eosin, 200 x).