An osteolytic lesion is seen in the distal metaphysis (with mild diaphyseal extension) of the right femur. The lesion shows mixed signal intensities on T1 and T2 weighted images and has multiloculated cystic appearance on T2 weighted images. Multiple foci of hemorrhage are seen within the lesion. It has well-defined superior and inferior margins (narrow zone of transition); however, there is irregular endosteal thinning along the anterior and posterior margins of the lesion. Periosteal reaction and small extra-osseous soft tissue component are also appreciable along the anterior and posterior margins of the lesion. The lesion shows mild diffusion restriction. Post-contrast study shows enhancement at the superior and inferior aspects of the lesion as well as in the adjacent bone. Adjacent right knee joint appears unremarkable. No skip lesion is seen in the visualized portion of the right femur. These MRI features are suggestive of a primary malignant bone neoplasm.