Presentation
Young woman presents with right lower extremity pain related to increased exercise. Concern for a bone stress injury.
Patient Data
Anterior and posterior views of the lower body from a bone scan show an abnormal intense focus of radiotracer uptake in the medial condyle/epicondyle of the distal right femur. The uptake is ovoid in morphology.
No other osseous abnormalities are present.
Frontal x-ray view of the right knee demonstrates a lucent lesion in the medial epicondyle. No sclerotic margin. The cortex appears to remain intact. No other acute findings.
Coronal MRI shows a T2 hyper intense lesion in the medial epicondyle. A small focus of metaphyseal cortical break through is present along the superior margin. There is marrow edema deep to the lesion. There is sub periosteal and soft tissue edema just superficial to the lesion.
Case Discussion
Initial bone scintigraphy shows abnormal intense radiotracer uptake in the medial condyle/epicondyle of the right knee. The uptake extends to the joint and is ovoid in morphology. There are no other abnormalities. This pattern of activity is non specific, but not suggestive of a stress fracture - the suspected clinical diagnosis. Hence x-ray was recommended for correlation.
X-ray revealed a lucent lesion in the medial epicondyle without cortical destruction.
MRI reveal the lesion to be hyperintense on T2 weighted sequences with aggressive features of bone marrow edema, small focus of cortical breakthrough, as well as overlying sub periosteal and soft tissue edema.
Combination of findings along with age of patient and location of lesion favored the diagnosis of GCT which was confirmed pathologically.
Patient was treated with surgical curretage and the cavity was packed with bone cement.