[Bone cysts-differential diagnosis and therapeutic approach].

The differential diagnosis of cystic lesions of the skeleton is multifarious. Besides patient age, the localization and radiologic morphology provide important information for a closer differentiation. Juvenile and aneurysmal bone cysts represent two frequent entities in growing patients. The fluid content of the cysts helps in distinguishing between juvenile and aneurysmal bone cysts. Whereas juvenile bone cysts contain clear fluid, the content of aneurysmal bone cysts consists of blood combined with solid tissue. With respect to progression, aneurysmal bone cysts show a higher activity than solitary bone cysts. The treatment of juvenile bone cysts usually consists of curettage including filling with bone replacement material. For aneurysmal bone cysts the additional use of adjuvants is recommended. Bone cement is preferably used for filling. It shows favorable properties for prophylaxis of recurrence and facilitates the recognition of relapses. Both juvenile and aneurysmal bone cysts often show recurrences.