Scintigraphic characteristics of non-ossifying fibroma in military recruits undergoing bone scintigraphy for suspected stress fractures and lower limb pains

Non-ossifying fibroma (NOF) is the most common fibrous bone lesion in children and young adults. This benign lesion is not a true neoplasm but is considered a developmental defect. Clinically, the lesion is asymptomatic and has a predilection for the long bones, particularly the femur and the tibia. NOF that ossify can show increased uptake on bone scintigraphy. Although the radiographic and histopathological findings of NOF have been well described, the scintigraphic findings of the abnormality have only been incidentally mentioned in the literature. To document the scintigraphic features of NOF in a group of military recruits undergoing bone scintigraphy for suspected stress fractures. Features to differentiate co-existent NOF and stress fractures lesions are discussed. Eighty-three military recruits, 67 male and 16 female, aged 18 to 22 years (mean, 19.4 years), who underwent ^99mTc-methylene diphosphonate bone scans for suspected stress fractures or because of pain of the lower limbs had 91 focal lesions on bone scan which on further evaluation demonstrated characteristic radiographic findings of NOF. We evaluated the anatomical site of the lesions, documented the intensity of uptake on bone scan and compared the findings with the radiographic description of the lesions. Comparison with the characteristic scintigraphic pattern of co-existent stress fracture lesions and with previously reported data was performed.