Reason: Synovial osteochondromatosis, evaluate for progression Again seen a lobulated mass occupying the anterior joint space and Hoffa's fat pad extending superiorly to the patellofemoral joint as well as posteriorly into the joint and semimembranosus gastrocnemius bursa. The mass appears to have increased in size since the prior exam, now occupying the majority of the joint space anteriorly with near-complete obliteration of Hoffa's fat pad. The mass extends along the posteromedial aspect of the proximal tibia, the pes anserine tendons, and the posterior aspect of the medial femoral condyle, similar to the prior exam. There has been an increase in size of the lesion along the tibiofemoral joint, with increased erosion of the fibular head. There is new erosion of the lateral, central, and medial tibial plateau as well as small erosions in the medial femoral condyle. The mass demonstrates abnormal increased heterogeneous signal intensity on the T2-weighted images, with peripheral nodular enhancement following gadolinium administration. Overall, these findings are consistent with progression of synovial chondromatosis.
Widespread synovitis consistent with patient's known history of synovial chondromatosis, progressed since the prior exam with increased bone erosion and obliteration of the joint space.