Aneurysmal bone cyst of the lumbar spine

Aneurysmal bone cysts (ABCs) account for 9% of benign bone tumors. They are tumor-like bone lesions, formed by blood-filled channels separated by connective tissue septa. Their prevalence peaks in adolescence, and they are slightly more common in girls than in boys. They are most commonly found in the metaphysis of long bones (50%) and the posterior spinal elements (12-30%). The symptons can be non-specific, butt his disease should be suspected in adolescents presenting with pain and bone swelling. On radiographs and nuclear magnetic resonance imaging, ABC appears as an expansive, lytic, agressive lesion with a sclerotic rim. Usually, the cortex is intact. They can present as multiloculated lesions with a "soap bubble" appearance and fluid-fluid levels. The definitive diagnosis is based on the histopathological features. There are different approaches to treatment depending on the lesion. Although ABCs are not malignant, they are aggressive, so prompt suspicion in pediatric patients is important for early treatment. We present 2 cases of ABCs involving the spine in adolescents to illustrate this condition.