Definition
A bone cyst is a fluid-filled cavity in the bone and is incorporated under tumor-like benign bone injuries. A distinction is also made between a simple (juvenile) and aneurysmatic bone cyst. As the name suggests, the clinical picture of a juvenile bone cyst occurs in children and adolescents and is located in the metaphysis.
This is the area between the diaphysis and pineal gland and includes the growth plate in children and adolescents. In most cases, the simple bone cyst is located on the humerus (50-70%) or femur (25%). Initially, the bone cysts are located directly on the growth plate; the more you grow, the further away (more distal) it is. In patients over 20 years of age, a juvenile bone cyst can also affect the kneecap, shoulder blade or ilium. The fluid in the cyst is serous and can be bloody-serous after a bone fracture.
Frequency
Only about 20% of bone cysts occur in the second decade of life, and most of the approximately 65% occur in the first ten years of life. Boys are affected twice as often as girls. Overall, juvenile bone cysts account for about three percent of all bone tumors.
Clinic
Since the juvenile bone cyst does not cause immediate symptoms, it is usually discovered by chance. However, it can rarely cause pain and swelling as well as movement restrictions. In 30 to 60% of cases, it is conspicuous by a fracture that has taken place.
In the upper arm
The juvenile bone cyst is a benign bone tumor most commonly located in the upper arm. The humerus is a long tubular bone in the human skeleton and, along with other long tubular bones such as the thigh, is a typical site of manifestation of juvenile bone cysts. In the upper arm itself, the juvenile bone cyst usually grows in the area of the metaphysis.
The metaphysis lies between the pineal gland, the region of the joint head, and the diaphysis, the bone shaft. The juvenile bone cyst is therefore initially located relatively close to the joint region and in the area of the fetal growth plate. In the further growth process, the juvenile bone cyst tends to shift towards the bone shaft.
