Abstract
Abstract Purpose: Fibrous dysplasia and simple bone cysts are rare diseases without established guidelines. Therefore, patients are usually treated based on the surgeon’s experience and the treatment may vary in each case. The purpose of this study is to summarize symptoms, treatment and outcome of the two diseases, to be able to use existing knowledge in further treatment of new patients. Methods: This is a retrospective cohort study of 47 patients (27 fibrous dysplasia and 20 simple bone cyst) with a lesion localized to the proximal femur. All patients were under 30 years old, and were recruited from a prospective register at The Norwegian Radium Hospital (Sarkomregisteret). Results: All patients who discovered their lesion due to a pathological bone fracture were 14 years or younger. 11 out of 13 patients were treated after established guidelines for bone fractures. The majority had no further symptoms, however three out of seven with fibrous dysplasia were in demand further treatment. In all cases where the lesion was an incidental finding, the patients were older than 18 years. Everyone (11 patients) was observed with no further problems, except one with fibrous dysplasia who developed permanent pain and had surgical treatment. Where pain was the reason for discovering the lesion the majority was observed. The main part had further symptoms with long-lasting pain or fracture (11 out of 13 patients with fibrous dysplasia, three out of seven with simple bone cyst). Conclusion: Lesions discovered incidentally were associated with an uncomplicated further course of disease. Patients with lesions discovered due to pathological fracture returned to normal function without pain after healed fracture.