Giant Aneurysmal Bone Cyst of the Right Femur about a Case

Aneurysmal bone cyst (ABC) is a rare bone tumor accounting for 1% - 4% of benign bone tumors. Its etiopathogenesis remains unknown. The main site is the metaphysis of the long bones. ABC occurs almost exclusively in young people, with a slight female predominance. We report an exceptional case of ABC of the femur with involvement of the right hip in a 16-year-old girl in the Medical Imaging Department of Pr Bocar Sidy Sall Hospital of Kati (Mali). We will discuss the clinical and radiological aspects of this pathology. Observation: Mrs N C., aged 16, was referred to the orthopaedic-traumatology department for an X-ray of the right thigh, indicated as having a large, disabling thigh. Clinical examination revealed a large thigh measuring 890 mm in circumference, compared with 300 mm on the contralateral side. Radiographically, the femur showed a blown appearance, with the cortex thinned and broken in places. Exceptionally, the lesion affected the entire femur. On CT scan, we found a voluminous fluid collection occupying the entire right femur, including the right femoral head and homolateral ischium. The cortex was interrupted in places, and the adjacent soft tissues were thinned or laminated, but not infiltrated. Histology revealed haemorrhagic and inflammatory elements compatible with the diagnosis of ABC. Conclusion: ABC is a tumor entity that is often difficult to diagnose. Medical imaging, topographical distribution and histology form an indissociable whole to establish a diagnosis of certainty.