Olecranon bursitis communicating with an olecranon cyst in rheumatoid arthritis

Nonseptic inflammation of the olecranon bursa is frequent because of its superficial location.(1) This olecranon bursitis can be due to variable causes such as trauma, overuse, inflammatory arthropathy, chronic degenerative osteoarthritis, rheumatoid arthritis (RA), and gout.(2-4) A cyst (or geode) is a subarticular cystic lesion, and this is often seen in osteoarthritis and RA.(5) Other forms of arthritis, such as hemophilia, calcium pyrophosphate deposition disease, and gout, can show cysts.(5-7) These cysts are usually small but can enlarge and reach 5 or 6 cm in diameter.(8) Although cysts are common in RA, cysts occurring in the olecranon have been rarely reported,(9-12) and most of them were related to spontaneous fractures through olecranon cysts.(9-11) To our knowledge, a report of communication between olecranon bursitis and an olecranon cyst has not been reported in the English literature. We present a case of olecranon bursitis in a 23-year-old rheumatoid patient in which communication with an olecranon cyst was confirmed on sonography and at surgery. On color scale sonography, compression with the ultrasound transducer on the bursa was useful for confirming the communication between the olecranon bursa and the cyst by observation of the color flow signal.