[Osteochondroma of the clavicle and pain syndrome of the shoulder. Apropos of a case. Review of the literature].

INTRODUCTION

Osteochondroma, a frequent benign tumor of the bone, is in most cases asymptomatic. Localization in the clavicle is extremely rare. The authors report an isolated case occurring in the coraco-clavicular area responsible for a painful shoulder syndrome evoking rotator cuff tendinitis.

METHODS

A 47 years female patient consulted for painful shoulder syndrome. Pain occurred following an effort and at night. On clinical examination, the area around the coracoid process was tender as was the supraspinatus fossa. Passive anterior elevation of the shoulder was limited to 150 degrees. She had a positive Job's sign as well as a painful << Gross armtest >>. Initial Radiological assessment showed no anomalies. Arthrographic CT scan revealed an expansive process compatible with osteochondroma. The lesion was in contact with the supraspinatus muscles and the coracoid process. Extraperiosteal resection was performed through a delto-pectoral approach. Recovery of a painless mobile joint was rapid.

DISCUSSION

Clavicular embryology is not yet well understood. The appearance of an exostosis at this localization seems to confirm that the clavicular cartilage behaves as an epiphyseal bone plate. The exostosis, which has a congenital origin, can appear, when it reaches a certain size or when it mechanically interferes with surrounding muscles and tendons. In our observation, the lesion led to irritation of the supraspinatus muscle leading to tendinitis. Diagnosis is usually made on standard roentgenographic evaluation. CT scan and MRI show a cartilaginous coating which should not exceed 10 mm in the case of a benign tumor. There exists a possibility of sarcomatous degeneration, but this is rare on the peripheral skeleton. Treatment should be performed by complete extraperiosteal resection of the exostosis along with its perichondral cover.

CONCLUSION

Clavicular localization of an osteochondroma is very rare. This case report illustrates the possibility of a painful shoulder syndrome associated with this lesion. This report also seems to suggest the hypothesis that the cartilage at this level behaves as an epiphyseal bone plate.