Sternocostoclavicular hyperostosis. A case report and review of the literature.

Sternocostoclavicular hyperostosis (SCCH) or intersternocostoclavicular ossification is a recently recognized disorder of unknown origin. SCCH is characterized by painful, condensing hypertrophy of the sternum, both clavicles, and the upper ribs. Since its original description by Sonozaki in 1974, approximately 40 cases have been reported, mainly in the Japanese literature. This peculiar hyperostotic syndrome is often misdiagnosed. The differentiation from osteitis deformans can be difficult. Clinically, the disease produces a swelling in the upper chest area with persistent, pulling pain exacerbated by cold and dampness. The condition is a nonspecific inflammatory syndrome. Radiographs usually show symmetric hyperostosis of the sternal portions of the clavicles, synostosis of the sternoclavicular joints, a thickened sternum, and varying degrees of involvement of the upper ribs and intercostoclavicular space. Biopsy specimens reveal hyperostotic sclerosis of the cancellous bone. Although the cause of the syndrome is unknown, clinical, radiologic, and histologic findings indicate that it represents a distinct entity. The treatment of SCCH remains symptomatic.