The ankle bone, (the talus) can develop tears in the cartilage lining of the joint, which then also form cysts in the bone underneath.
These are termed Osteochondral defects, or an OCD.
This is usually due to an injury such as a sprain. These often cause swelling and pain, and can be associated with catching or sharp intermittent pain in the ankle.
An OCD has a natural history of not healing and progressing to more advanced cartilage and leading to arthritis. A small number may heal with rest and protection.