A.I.E. Ramautar¹, N.M. Appelman-Dijkstra¹ , S. Lakerveld¹, P.A. Valkema¹, M. Snel¹, M.A. Schroijen¹ , E.M. Winter¹, N.A.T. Hamdy¹

¹Centre for Bone Quality Leiden University Medical Centre, Department of Medicine, Division of Endocrinology, Leiden, The Netherlands

Sternocostoclavicular hyperostosis (SCCH) is a rare inflammatory bone disorder due to a chronic sterile osteomyelitis of unknown origin, leading to hyperostosis and sclerosis of sternum, medial end of clavicles and first ribs. Other areas of the axial skeleton such as mandible and vertebrae may also be affected. We report the clinical characteristics of a large single centre Dutch cohort of 189 patients with an established diagnosis of SCCH on the basis of characteristic clinical, scintigraphic and radiological features.

Data on gender, age at first symptoms and at diagnosis, clinical manifestations, shoulder girdle function, and disease-related incapacity for work, were retrieved from medical records.

The cohort consisted of 189 patients, predominantly female (88%), with a median age of 37 years (range 17-70) at first symptom. Most common first symptoms were pain in 159 patients (85%), local inflammatory changes in 77 (41%), impairment of shoulder girdle function in 63(34%), and bone swelling in the SCC region in 54 (29%). At time of diagnosis, which occurred after a mean delay of 5±5 years, main clinical manifestations were chronic pain of variable severity in the SCC region in 183(95%), bony swelling of affected areas of the anterior chest wall in 124(66%) and restricted shoulder girdle function in 81 patients(43%).  64 patients(35%)  had palmoplantar pustulosis, and 47 (25%) had an autoimmune disease, mainly psoriasis (n=15, 8%).  The most commonly affected sites were the medial end of the clavicles in 76% of patients, followed by medial end of first ribs in 64%. Mandible and vertebrae were less commonly affected. 

SCCH is a rare inflammatory bone disorder associated with variable degrees of disability leading to potential limitations in functional capacity to work due to chronic pain and impairment in shoulder girdle function. Delayed diagnosis is common because of failure to recognize the rare but distinctive clinical features of the disorder. This may result in irreversible structural changes in affected bone and secondary arthritis is adjacent joint associated with potentially debilitating chronic symptoms.  Early diagnosis and early institution of therapy may positively influence prognosis by preventing disease progression, although this remains to be established by long-term follow-up studies.