Relatively well-defined, oval-shaped, eccentrically located, expansile, irregular marginated, T1 low/ T2 intermediate to slightly high/ PD FS high signal intensity lesion measuring ~ 5.6 x 4.6 x 3.3 cm noted on the epi-metaphysis of the medial aspect of lower end of femur. There is peripheral T1 low signal intensity rim. There are multiple, tiny, subcentimetric, T2/ PD FS high signal intensity areas noted within the lesion suggesting cystic areas. There is no fluid-fluid level.
On GRE, there is no blooming artefact. Post contrast study shows homogenous enhancement of the lesion. There is cortical thinning with breach noted at the medial, anterior and posterior aspects of the femur associated with enhancing, soft tissue component measuring ~ 1.9 x 0.5 cm protruding outwards from the margin of cortical breach just at the juxtacortical position at the medial aspect. Medially, there is loss of interface with vastas medialis muscle while posteriorly there is loss of interface with the medial head of gastrocnemius. The lesion is ~ 2.1 mm away from the articular surface of the femur.
Multiple, ill-defined, patchy, altered, PD FS high signal intensities which show enhancement on post contrast study are noted in the peri-lesional area in the distal third of femur suggesting bone marrow oedema. There is minimal knee joint effusion.