What is a enthesopathic fibrocystic foci on the posterior of the humeral head (associated with lots of pain in my shoulder)?

Humeral Cysts: Cystic changes are seen in the head of the humerus on MRI scan of the mature shoulder in the bone marrow of the greater tuberosity where the rotator cuff tendons insert. In medicine, an enthesopathy refers to any disorder involving the attachment of a tendon or ligament to a bone called an enthesis. When inflamed it is called enthesitis. By age 50 partial tears of the RCT are seen on many MRI's.