Long Bone Metastases From Malignant Tumors Imaging Features And Differential Diagnosis

Objective: By analyzing the clinical and imaging data of pathologically confirmed long bone metastases patients,the characteristics of the images and the differences between different sources were summarized to improve the understanding and diagnostic ability.Methods: This study was approved by the local ethical board.From July 2010 to February 2018,the patients with pathology-confirmed long bone metastases in our hospital were retrospectively analyzed.163 patients(81 male,82 female;age range,30-84 years;average age,58.68 ± 9.80 years)were included in this study.154 patients underwent X-ray or CT examination,98 underwent MR,and 54 underwent MR enhancement.Clinical and imaging features of the lesions were analyzed,including clinical,morphological and signal intensity characteristics.Then the features of lung cancer(77 cases),breast cancer(29 cases),and renal cell cancer(19 cases)were compared.Finally,imaging features of the patients with fewer cases were described.Statistical analysis was performed using SPSS 22.0.The Kruskal-Wallis H test were used for the time interval and height-to-width ratio in the three groups of lung cancer,breast cancer and renal cancer group,and scatter plots were drawn.The Chi-Square Test or Fisher’s exact test was used for the enumeration data.Results: 1.117 patients were admitted to hospital with discomfort of the metastatic sites,and 46 patients were found metastases after operation or treatment.132 lesions were located in the epiphysis and 31 in the diaphysis.111 were eccentric.121 lesions were osteolytic destruction,16 were osteogenic destruction,other 17 were mixed destruction,and 38 of them were expansile destruction.The cortical bones were interrupted in 105 lesions,of which 19 had pathological fracture and 25 had cookie-bite sign.8 cases had periosteal reaction.86 lesions demonstrated soft tissue mass and other 68 lesions without soft tissue mass.In 87 lesions,T1 W were slightly hypointense,T2 W were slightly hyperintense or isointense.In 9 lesions,T1 W and T2 W were hypointense,and in other 2 lesions,T1 W,T2W were slightly hyperintense.T1 W,T2W signal were not uniform in 89 cases.On T2 W,25 lesions demonstrated soap bubble hyperintense,of which 2 cases showed fluid-fluid levels.62 lesions demonstrated linear hypointense separation and 15 lesions demonstrated flow-void sign.On the T2 W fat suppression sequence,edema signals were seen around the lesions in 84 cases.41 cases were significantly enhancement,13 cases were mildly or moderately enhancement,of which 51 cases were inhomogeneous enhancement.2.In the lung cancer group(77 cases),the breast group(29 cases),and the renal cancer group(19 cases),the distribution of firstly found primary or metastatic lesions in the clinic,and the time interval of metastases in the firstly found primary lesions were different,with statistical significance(P<0.05).The difference in the height-to-width ratio distribution among the three groups were statistically significant.There were also statistically significant differences in destruction,swell,cortical continuity,pathological fracture,cookie-bite sign,soft tissue mass,soap bubble sign,and flow-void sign among the three groups(P<0.05).3.The gastrointestinal cancer sources(8 cases)were 7 cases of osteolytic destruction,1 case of osteogenic destruction,1 case of soft tissue mass penetrated the cortex,4 cases of mildly enhancement,and other 4 cases of obvious enhancement.Cervical cancer sources(7 cases)were all osteolytic destruction,and were significantly inhomogeneous enhancement on MR.Prostate cancer sources(4 cases)were osteogenic destruction.The sources of hepatocellular carcinoma(4 cases)was osteolytic destruction,and 3 cases showed expansile changes with obvious soft tissue mass.The sources of pharyngeal tumor(4 cases)showed osteolytic destruction,and hyperintense areas were found in the central region on T2 W.The sources of thyroid cancer(4 cases)was similar to that of renal cancer.Adrenal adenocarcinoma originated(1 case)with mixed destruction and soap bubble sign.Melanoma origin(1 case)was osteolytic destruction,accompanied by pathological fracture,with slightly hyperintense area on T1 W and T2 W.Conclusion: Long bone metastases mainly occur in the right proximal femur and humerus,mostly with osteolytic destruction.Some sources may appear expansile change,cookiebite sign,soap bubble sign,fluid-fluid levels.The time interval,growth pattern,bone destruction pattern,pathological fracture,soap bubble sign and flow-void sign could distinguish the origin of lung cancer,breast cancer and renal cancer.Other sources also differed in bone destruction pattern,soft tissue mass and MR signal characteristics.