Aneurysmal bone cyst (ABC) is a descriptive composed of two terms: “Aneurysmal” which means expansion and the word “cyst” which means cavities, the particularity of this cavities is the presence of a “fluid-fluid” level.” However, it is neither an aneurysm nor a cyst, but a true neoplasm.

ABC is a rare tumor which account of 1% of all bone tumors with an incidence of 0.14 per 100,000 individuals and a prevalence of 0.32 cases per 100,000 individuals. The vast majority of ABC occurs in children and young individuals, and has a male to female ratio of 1:1.16 [1]

The classic presentation includes pain and swelling, a palpable masse, paresthesia and scoliosis in spinal location. it can be revealed by a pathological fracture in rare cases.

On radiographs features, ABC is shown as are lytic, expansile, geographical, lobulated, metaphyseal-based lesions and have a distinct sclerotic border, it has septations that can or cannot be seen on this imaging modality. Different types of periosteal reaction may be seen [2,3].

MRI is the diagnostic modality of choice for the diagnosis of ABC by showing the internal composition of the cystic lesion with the pathognomonic “fluid-fluid” level, the evidence of the septations, and the nodularity enhancement; the extension of the lesion (physical, epiphyseal, soft tissue and vertebral canal extension), and the evidence of perilesional oedema [4].