Aggressive development of an aneurysmal bone cyst of the proximal femur in a paediatric patient: a case report.

We report development of an aneurysmal bone cyst (ABC) that was located in the proximal region of the femur in an 11-year-old girl. Over a period of 30 weeks, the ABC showed fulminant local progression, with destruction of the bone, which led to an abrupt loss of function of the left hip. The standard tumour treatment protocol was followed. We performed embolisation of the tumour followed by a biopsy, which confirmed the diagnosis of ABC. The outcome was negative with total destruction of the proximal third of the femur, despite repeating the embolisation. Because of the unfavourable local progression, a second biopsy was performed and we reconfirmed the initial diagnosis. The final decision regarding the therapeutic approach was total hip arthroplasty with femoral reconstruction with a prosthesis. Following this treatment, the patient's outcome was favourable, with complete recovery of function and no local relapse.