The right acetabulum as well as the adjoining superior pubic ramus and right iliac bones show multi-locular expansile cystic lesion with thin non-sclerotic rim and narrow zone of transition. No evident cortical break through or extra-osseous soft tissue component. The lesion shows hypointense T1 and hyperintense T2 / STIR signal with typical characteristic fluid / fluid levels. The lesion is seen, predominantly within the pelvic cavity with indentation of urinary bladder. Mild right hip joint effusion. Normal proximal right femur with smooth regular outline. Normal left hip.