The imaging manifestations of giant cell tumor of bone are as follows: a. X-rays show eccentric, expansile and osteolytic lesions in the epiphysis of long bones, and lesions in long bones occasionally show matrix calcification. Giant cell tumor of bone may show soap bubble-like changes in cancellous bone, and lesions in sacrum and pelvis show osteolytic changes, often involving nearby soft tissues and sacroiliac and hip joints. CT can clearly show the cortical thinning and penetration of the cortex, and MRI can show the extent of lesions in the bone, the boundaries of soft tissue masses and joint involvement. Typical MR scan shows low to medium signal in T1-weighted image and medium to high signal in T2-weighted image. The tumor contains a large amount of iron-containing heme, which shows low signal in both T1 and T2-weighted images.