Extensor carpi ulnaris tenosynovitis caused by the tip of an oversized ulnar styloid: a case report.

Background Degenerative tendinopathy of the extensor carpi ulnaris (ECU) produced by the tip of an oversized ulnar styloid has not been formerly reported. Case Description We report an uncommon case of an injury to the ECU tendon that was related to a prominent oversized ulnar styloid. The patient's symptoms improved following resection of the styloid process. Literature Review Our case differs from previous reports in that it involves an uninjured oversized ulnar styloid that damaged the overlying ECU tendon with no apparent instability. Clinical Relevance Besides ulnar styloid impaction syndrome, the diagnosis of ECU tenosynovitis should also be considered in patients with ulnar-side pain and an oversized ulnar styloid.