A bone cyst is a noncancerous bone tumor that develops as a fluid-filled sac, or cyst, within the bone tissue. There are two major forms of bone cysts: unicameral, which can affect people of any age, and aneurysmal, which typically arise in people under age 20, according to MassGeneral Hospital for Children. People who develop bone cyst symptoms should receive further evaluation and care from a doctor.
No Symptoms
People who develop a unicameral bone cyst typically do not experience symptoms, Children's Hospital Boston reports. As of 2010, it is unclear why bone cysts develop, though factors may include growth plate or circulation problems or repeated bone trauma.
Pain
An aneurysmal bone cyst can cause pain, the Merck Manuals Online Medical Library explains. Pain sensations are typically localized to the site of the bone cyst and may worsen during physical activity. Initially, sensations of pain may be mild. As the bone cyst continues to grow, pain typically intensifies.
Swelling
Swelling can occur as a symptom of an aneurysmal bone cyst, MassGeneral Hospital for Children warns. The region of skin surrounding the affected bone can appear inflamed, puffy or enlarged and can be tender to the touch. Physical activities involving the affected limb can exacerbate swelling.
Fracture
A unicameral bone cyst may cause degradation of the affected bone, the American Academy of Orthopaedic Surgeons reports. If this occurs, people can develop a bone fracture at the site of a bone cyst. Bone fracture symptoms can include physical deformity, swelling or pain. These symptoms may be most apparent when a person places weight on the affected limb.
