Decompensation of a supinator syndrome by a submuscular lipoma. A rare differential diagnosis of elbow pain.

Important differential diagnoses to epicondylitis humeri radialis are the n erve compression syndromes of the ellbow. After a long period of conservati ve treatment, paresis of the motor branch of nervus radialis in this case l ed to the diagnosis and surgical treatment showing an unknown submuscular l ipoma as the cause of a supinator syndrome with paresis of the finger exten sors. In cases of therapy-resistant pain of the ellbow, especially resistan t to the conservative therapy of an epicondylitis humeri radialis, a nontra umatic supinator syndrome should be considered as a differential diagnosis. A tumor as the cause of a compression syndrome of the motor branch of the nervus radialis is very rare.