Simple bone cysts: factors of age dependency.

Patient age plays a significant role in the presentation and clinical behavior of bone cysts. In children, cysts behave more aggressively than in adults and the recurrence rate for patients in the first decade of life is four times that in the adolescent. Simple bone cysts are less frequent after 17 years of age and 80% of cysts in the young are located in the proximal end of the shaft of the humerus and femur. Pathological fractures will call attention to the cyst and the highest incidence of fractures is in childhood (0--10 years).