Milwaukee shoulder syndrome

Milwaukee shoulder syndrome (MSS) (apatite-associated destructive arthritis/Basic calcium phosphate (BCP) crystal arthritis/rapid destructive arthritis of the shoulder) is a rare rheumatological condition similar to pseudogout, associated with periarticular or intra-articular deposition of hydroxyapatite or basic calcium phosphate (BCP) crystals. While primarily associated with the shoulder joint, it can affect any joint in the body below the head.

Source: Wikipedia — Milwaukee shoulder syndrome (CC BY-SA 4.0)