Abstract
Aneurysmal bone cysts are rare lesions, comprising one to six percent of primary bone tumors. Despite benign, those may be locally aggressive. We report a pediatric case with an atypical presentation. The patient was a seven-year-old boy, admitted to an emergency room due to right inguinal pain, without a history of trauma. The symptoms had acute onset and worsened gradually for five days. Radiographs revealed a cystic lesion on the proximal right femur and two longitudinal fractures. After further diagnostic work-up and given the probable diagnosis of an aneurysmal bone cyst, surgical treatment was performed. The diagnosis was then confirmed by histopathological analysis. After surgery, the patient maintained severe pain, having an important range of motion (ROM) and muscular strength reduction on the affected limb. As so, the patient engaged in a daily tailored Physical Medicine and Rehabilitation (PMR) program, for four months. After concluding the treatment plan, the patient was asymptomatic: recovery of both ROM and muscular strength was achieved, as well as the ability to return to previous daily-life activities. This is a paradigmatic case in which a rare condition with a rare presentation was displayed after several others were ruled out, requiring a multidisciplinary approach.