Prevalence of aneurysmal and solitary bone cysts in young patients.

Aneurysmal and solitary bone cysts develop most commonly during skeletal growth. The objective of our epidemiologic study was to evaluate the prevalence, recurrence rate, and probability of recurrence-free survival for aneurysmal and solitary bone cysts in young patients. We did a population-based analysis of 141 histologically confirmed cases. Seventy-three patients with aneurysmal bone cysts and 68 patients with solitary bone cysts were registered. The annual prevalence was 0.32 per 100,000 individuals (range, 0-1.238) for aneurysmal cysts, with a 1.8:1 male to female ratio and a median age of the patients of 11.1 years (range, 1-19.7 years). For solitary bone cysts, the calculated annual prevalence was 0.30 (range, 0-0.963) with a median age of the patients of 1.1 years (range, 0.5-19.9) and a 1.96:1 male to female ratio. Recurrent lesions occurred frequently in young males. Secondary aneurysmal bone cysts were observed only in females. During skeletal growth, aneurysmal and juvenile bone cysts more often occur in males with a peak prevalence at approximately 11 years of age. A greater prevalence of aneurysmal bone cysts in young individuals is associated with skeletal growth and immaturity. Young age and male gender are associated with an increased risk of local recurrence.