Clavicular Osteochondroma: Extremely Rare Cause of Impingement Syndrome

Impingement syndrome is one of the most common pain disorders of the shoulder; it may be due by structural alteration of acromion, coracoacromial ligament, acromioclavicular joint, biceps tendon, or coracoid process; however, in rare cases, impingement syndrome may be due also by benign tumors such as osteochondroma.

We presented a case of 27-year-old male with clavicular impingement syndrome secondary to osteochondroma. He received conservative treatment before the diagnosis of the osteochondroma. Radiograph, computed tomography, and magnetic resonance imaging of the shoulder were performed. As the failure of non-operative treatment, the patient underwent to open surgical procedure with the excision of the osteochondroma.

Clavicular osteochondroma is a very rare cause of impingement syndrome, and it may cause severe shoulder impingement with reduction of the range of movements. Osteochondroma may be complicated by a number of secondary abnormalities, including inflammatory changes of the bursa exostotica ("exostosis bursata") covering the cartilaginous cap, pressure on nerves, blood vessels, and the adjacent bone. The least common complication seen in <1% of cases of solitary lesions is malignant transformation to chondrosarcoma. The diagnosis of clavicular osteochondroma should be considered in any patient with shoulder impingement syndrome, and good functional results can be expected following total excision.