I had a pea-sized mass removed from my right ankle. The pathologist’s report called it a synovial osteochondromatosis. The surgeon explained that this is an overgrowth of the fluid in my joint that hardens to form bits of cartilage and bone. Now that it’s gone, I can move my ankle again. What are the chances it will come back?

Synovial osteochondromatosis occurs in three phases. First, there is the overgrowth of the synovium, the slippery fluid that keeps your joints moving smoothly. Next, the extra synovium begins to form bumps and lumps that can stick to the cartilage. And finally, these masses can break loose and move out of the joint.

What happens over time is called the natural history of a condition. In the case of synovial osteochondromatosis, the body can break down and absorbs these tiny masses. Most of the time, they interfere with motion and have to be surgically removed. Whether they are resorbed naturally by the body or surgically removed, osteochondral masses can grow back.

They can even become malignant. That only happens about five per cent of the time but it’s something to watch out for. No one knows why this transformation from benign mass to malignant tumor (chondrosarcoma) occurs. There isn’t a way to predict who might develop a malignancy. That’s why the masses are removed and then observed closely afterwards.