A 52-year-old lady presents to her GP complaining of a swollen left knee. She is referred for an X-ray that demonstrates a joint effusion and moderate degenerative change in the medial compartment. She later goes on to have an MRI scan which demonstrates abnormal frond-like appearance of the synovium. This is of high T1 and high T2 signal and low signal on the STIR sequence. Which of the following is true about this condition?