A Non-ossifying Fibroma and a Stress Fracture of the Femur Mimicking Bone Malignancy in a Child

Herein, we report a rare case of a stress fracture through a pre-existing non-ossifying fibroma (NOF) of the femur of a 12-year-old child that raised suspicion of a malignancy. Although NOFs are very frequent, in the vast majority of cases, they are completely asymptomatic. When encountered in a painful area, especially if combined with atypical radiographic features, they may mimic a malignancy. We discuss the radiographic findings, the differential diagnosis, and the relevant points of the patient's history that helped to establish the diagnosis.