Stress fracture of the clavicle associated with sternocostoclavicular hyperostosis combined with bony ankylosis of the acromioclavicular joint and ossification of the coracoclavicular ligament.

Sternocostoclavicular hyperostosis (SCCH) has been reported in patients with pustulotic arthro-osteitis, but there are few reports of marked ossification of the lateral part of the clavicle. Here, we report a case of stress fracture in a patient with SCCH with marked ossification of the lateral part of the clavicle. In this case, the clavicular fracture was proximal and no dislocation. Conservative treatment with a clavicle band and the administration of corticosteroids resulted in rapid symptom improvement. Eight months later, the patient had no difficulty in daily life, but X-rays showed that bone fusion was not complete. Therefore, it is necessary to carefully follow-up such patients for any recurrence of symptoms and radiographic changes.