| ObjectiveSummarize the imaging characteristics of vascular tumors of bone and correlate the imaging findings to the pathologic grade of benign, malignant vascular tumors, aim to improve the diagnosis and differential diagnosis.Materials and methodsA retrospective study was performed on the imaging features of 44 patients with histological diagnosis of bone hemangiomas (BH) including cavernous hemangioma 32 cases, arteriovenous hemangioma 8 cases, venous hemangioma 3 cases, capillary hemangioma 1 case, and 21 patients with malignant vascular tumors of bone(MVTB). MVTB were divided into low-grade 12 cases and high-grade 9 cases. Fifty-nine patients had CT examination and 55 patients had MR scan.53 patients had dynamic contrast-enhanced imaging. The imaging studies were assessed for the tumor location, multifocality, matrix (lytic, sclerotic), expansion, presence of residual bone, margin, cortex, peripheral sclerosis, periosteal reaction, pathologic fracture, signal intensity of images on T1- and T2-weighted sequences compared to the intensity of the surrounding muscle, presence of macroscopic fat, massive shape/vessel malformation, signal void, necrotic or cystic, hemorrhagic component, peritumoral signal intensity, intensity of enhancement. The imaging features of BH and MVTB were analyzed by SPSS 20 for Windows software, in order to observe the differences between them.ResultsOf 44 cases of BH, the soft tissue mass were iso-high density in 30 cases, iso-density in 6 cases, low-density in 1 case, and high-density in 1 case on CT scans, iso-low signal intensity on T1WI and high-signal on T2WI in all cases. Of 32 cases of CH,21 cases mainly occurred in the spine and skull (65.6%).4 cases were multiple. All cases showed osteolytic bone destruction. Expansion was seen in 20 cases (62.5%). Residual bone was seen in 27 cases (84.3%), which appeared as typical "radiating" "lattice-like" shape in 12 cases (occurred in the spine, skull), web-like, "honeycomb" or "soap bubble" shape in 7 cases, "gourd-like" shape in 1 case when cortical bone was involved; Peripheral sclerosis was seen in 13 cases, bone destruction in 19 cases, periosteal reaction in 1 case, pathologic fracture in 5 cases, well-defined edge in 25 cases (87.5%), fat and massive shape in 4 cases, soft tissue mass inside of the bone destruction region in 25 cases (78.1%), typical soft tissue hemangiomas in 3 cases, slightly inhomogeneous enhancement in 16 cases and progressive enhancement in 3 cases on enhanced CT/MR. AVH with 8 cases mainly occurred in pelvis, long bones (75%). One case was multiple. All cases showed osteolytic bone destruction with large flake shape in 7 cases (87.5%). Expansion was seen in 3 cases. Residual bone was seen in 6 cases (75%) with web-like, "farfetched-like" shape in 5 cases, peripheral sclerosis in 5 cases (62.5%), bone destruction in 7 cases (87.5%), periosteal reaction in 1 case, pathologic fracture in 2 cases, well-defined edge in 6 cases (75%), fat and massive shape in 3 cases, signal voids in 2 cases. Soft tissue mass outside of the bone destruction region in 5 cases (62.5%), slightly inhomogeneous enhancement in 5 cases on enhanced CT/MR. Three cases of VH patients occurred in the clavicle, ribs, humerus, respectively. Osteolytic bone destruction was seen in 2 cases, osteoblastic bone destruction in 1 case, expansion in 3 cases, residual bone and cortical bone destruction in each 2 cases, well-defined edge and soft tissue mass outside of the bone destruction region in each case, slightly heterogeneous enhancement in 1 case. One case with CPH occurred in the tibia and fibula, showed multiple, osteolytic bone destruction, ill-defined, and formed soft tissue mass outside of the bone destruction region.LMT showed multifocal (55.6%) and well-defined (66.7%) lesion with residual bone (77.8%), peripheral sclerosis (77.8%) and slightly inhomogeneous enhancement (87.5%), compared with those of HMT with 8.33%,41.7%,33.3%,41.7% and 8.33% respectively. Also, HMT appeared as ill-defined (58.3%), macroscopic necrosis/cystic (91.7%) or hemorrhage (25%) lesion, extra-osseous soft tissue tumors (66.7%), and obviously inhomogeneous enhancement (91.7%), compared with those of LMT with 33.3%,42.9%,0%,22.2%, and 12.5% respectively. The incidence of expansion (55.6%, 50.0%), disrupted cortex (88.9%,100%), periosteal reaction (11.1%,0), peritumoral signal intensity (71.4%,83.3%), and pathological fracture (11.1%,16.7%), massive shape/vessel malformation (11.1%,16.7%), homogeneous enhancement (3.33%,5.0%) in LMT and HMT was almost similar.BH occurred mainly in the axial skeleton (29 cases,65.9%), and MVTB occured mainly in bone (14 cases,66.7%). BH had no cases of necrosis/cystic or hemorrhage, peritumoral edema/change, which were seen above in MVTB 14 cases (73.7%),3 cases (15.8%),15 cases (78.4%), respectively. MVTB had no fat and signal void which was seen in BH of 6 cases (13.6%),2 (5.56%). Comparative analysis between the two groups:the remaining bone, ill-defined, cortical destruction and enhancement shape are statistically significant (P<0.05) between BH and MVTB. Multiple expansion, peripheral sclerosis, periosteal reaction, massive shape/vessel malformation, pathological fractures and extra-osseouss soft tissue mass showed no significant difference (P>0.05) between the two groups.Conclusion1. There are some imaging differences between the subtypes of BH. CH often occurs in the spine and skull, appearing as typical radiating and lattice-like coarse trabecular pattern, respectively. While occurring in other lesions, Expansion, "honeycomb-like" "soap bubble-like" or "web-like" residual bone, massive or irregular shape, and intra-osseouss soft tissue mass are usually seen. Cortical bone destruction, accompanied soft tissue hemangiomas and progressive enhancement after enhancement are rarely seen. AVH usually occur in the pelvis, long bones. Cortical bone destruction is broader. Residual bone is usually seen with "farfetched-like""web-like" shape, and often accompanied by signal void and massive shape/vessel malformation, interruptting cortex and forming extraosseous soft tissue mass. VH might be osteolytic or osteoblastic bone destruction. CPH might be homogeneous enhancement on enhanced CT or MR.2. Compared with HMT, LMT tends to have multifocal and well-defined lesions with residual bone tissue, peripheral sclerosis and slightly hetergeneous enhancement, whereas HMT is more likely to be associated ill-defined, necrosis/cystic or hemorrhagic component, and often presents with extraosseouss soft tissue mass and obviously hetergeneous enhancement.3. Occurring in axial skeleton and the presence of well-defined edge, residual bone tissue, fat, massive or irregular shape/flow void, and slightly heterogeneous enhancement suggests BH. Occurring in bone and the presence of necrosis/cystic or hemorrhagic component, peritumoral edema, ill-defined edge, cortical destruction and obviously heterogeneous enhancement highly suggests MVTB.4. CT combined with MR examination can makes the assessment of primary bone tumor vasculature better. CT is easy to observe the features of bone destruction, and MRI show the scope of lesions involvement, signal characteristics and enhancement style of soft tissue mass. |
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