Stress fractures presenting as tumours: a retrospective analysis of 22 cases

Abstract

Frequently, the imaging features of stress fractures may be misinterpreted as tumour-like lesions. The aim of this study was to analyse the quality of different examinations in detecting stress fractures mimicking tumour-like lesions in magnetic resonance imaging (MRI). We evaluated 22 cases which were referred to our department with the suspected diagnosis of bone tumours turning out to be stress fractures. Whenever the MRI did not lead to a diagnosis after a second review, computed tomography (CT) scans and, if still required, additional examinations were performed until the fracture was detected. A stress fracture was diagnosed in 15 cases after the additional CT scan, in five cases with the review of the MRI and in two cases with a combination of several examinations. Especially in stress fractures of the tibia and the femur, CT scanning was essential for making a diagnosis by detecting the fracture line. Bone scans and biopsies, in contrast, were not helpful in making a correct diagnosis.

Fig. 1

a A 59-year-old female patient having pain with a history of breast cancer. The T1-w fat sat post contrast shows circumscribed gadolinium enhancement suspicious of metastasis. b The computed tomography (CT) scan could identify the fracture line

Fig. 2

A 68-year-old female with acute onset of low back pain one month prior to presentation. The CT scan shows the insufficiency fracture of the sacrum

Fig. 3

a Sagittal short inversion time inversion recovery (STIR) sequence of the lower leg of a 24-year-old female having pain in the lower left leg for 2 months after taking up jogging. Diffuse hyperintensity in the marrow of the proximal tibia as well as in the surrounding soft tissues. A fracture line could not be detected. b In the same patient, the fracture line and callus formation (arrow) in the thin-layer CT (scan) revealed the diagnosis of stress fracture