There is a focal lobulated space occupying lesion in distal metaphysis of left femur. The lesion is hyper intense on T2, STIR and fat-suppressed T1-weighted; and iso- to hypo-intense on T1-weighted images with moderate contrast enhancement on post contrast images. The lesion does not show abnormal restriction on DWI. It has peripheral low signal intensity rim (corresponding to radiographic sclerosis) along its medial aspect and has multiple small focal internal hypo-intense areas (fibrosis/sclerosis?). Cortical interruption is noted along the anteroposterior and lateral aspects of the lesion; however, no significant extra-osseous soft tissue component is seen. No hemorrhage, necrosis, or fluid-fluid levels are noted in the lesion.
Based on these imaging features, a list of differential diagnoses including atypical GCT, fibrous dysplasia, ABC or chondromyxoid fibroma was given.