Bone Cyst

Excerpt

Bone cysts are often asymptomatic and found incidentally on radiographs. Sometimes, they may present with pain due to repeated hemorrhages or pathological fracture. Bone cysts are inclusive of but not limited to the simple/unicameral bone cyst (SBC/UBC) and aneurysmal bone cyst (ABC).

A simple bone cyst is a solitary fluid-filled; a benign bone cyst which may be unicameral (single chamber) or septated. It can involve any bone of extremities, the most common site being proximal humerus and proximal femur. In adults, the ilium and calcaneus are common locations. These lesions are most active during growth spurts and are known to heal spontaneously after bone maturity. Two-thirds of UBCs present with a fracture. UBCs in flat bones are often asymptomatic unless detected incidentally on imaging.

An aneurysmal bone cyst is a rare, locally destructive, blood-filled, benign cystic bone tumor. It involves the metaphysis of long bones in children and young adults. They can involve any bone, but the most common sites are the distal femur, proximal tibia, proximal humerus, and spine. Most cases present with mild to moderate pain. The rapid growth of lesion may mimic malignancy. Spinal lesions may cause radicular pain or neurologic deficits. They often involve posterior elements of the vertebral bodies. Exceptionally, ABC can also arise in soft tissue.