Differential CT and MR imaging diagnosis between low- and high-grade malignant vascular tumors of bone

OBJECTIVE To investigate the CT and MR imaging findings and differential diagnosis of malignant vascular tumors of bone. MATERIALS AND METHODS CT and MR imaging findings of 18 patients with histopathology-proven malignant vascular tumors of bone were examined. Assessed image features included age, sex, location, CT findings, and MR imaging appearances and dynamic contrast-enhanced MR imaging. RESULTS The study group comprised 18 cases, of which 7 were categorized as low-grade malignant vascular tumors (LMT), and 11 were categorized as high-grade malignant vascular tumors (HMT). Malignant vascular tumors of bone showed osteolytic lesions with heterogeneous signs and enhancement, and frequently associated with soft tissue masses and peritumorous edema. The mean age of patient was respectively 34.7 years in LMT with 3 patients younger than 20 and 49.9 years in HMT with 3 patients older than 60 years. The mean lesion diameter was 3.6 cm (range 2-7.2) in LMT with two lesions <3 cm and 7.1 cm (range 3-13) in HMT with 3 lesions greater than 10 cm. LMT showed multifocal (57.1 %) and well-defined (71.5 %) lesions with residual bone (57.1 %), peripheral sclerosis (85.7 %), and slightly hetergeneous enhancement (71.4 %), compared to those of HMT with 9.1, 45.5, 27.3, and 72.7 %, and 9.1 % respectively. Also, HMT appeared as expansive (54.5 %), ill-defined (54.5 %), macroscopic necrosis/cystic (81.8 %) or hemorrhagic (27.3 %) lesion with pathological fracture (27.3 %), and often presented with obviously hetergeneous enhancement (81.8 %), compared to those of LMT with 42.9, 28.6, 42.9, 0, 14.3 and 14.3 % respectively. CONCLUSIONS There are some differences in the imaging features between LMT and HMT, while unifocal/multifocal, expansive, ill-defined, necrosis/cystic, hemorrhagic features with age, lesion diameter, peripheral sclerosis, residual bone tissue, pathological fracture and slightly/obviously hetergeneous enhancement highly suggest their differential diagnosis.