Comparision of CTfindings of multiple myeloma bone lesions and other osteolytic metastatatic bone lesions

Multiple myeloma is malign disease characterized by abnormal proliferation of plasma cells in the bone marrow. Osteolytic metastases are one of the most common malign tumors of bones like multiple myeloma. It is important to differantiate between this two clinical conditions because their treatment and clinical assessment are different from each other. We aimed in this study to distunguish lytic lesions of multiple myeloma from metastases using CT findings. In our study, CT imaging findings that belong to patients diagnosed multiple myeloma or lytic metastasis in between July 2007 and November 2018 were evaluated by two different observer according to independent variables previously defined. In our study, bone dansity area in the lesion was seen metastatic lesions more than multiple myeloma lesions (metastasis:%85.2, myeloma: %19, p<0.001) (OR: 25.88, CI: 13.73-48.75, p <0.001, R2:.516). Also, perilesional sclerosis and unsharp contour features were seen metastatic patients more than myeloma patients(%38.9 - %13.2 p <0.001 and %34.6 - %9.1 p <0,001) .In addition to this findings, heterogenous internal structure feature in the lesion was seen metastatic patients more than myleoma patients in both contrast CT scans and non-contrast CT scans ( %81.6 - %29.4 p<0.001 and %60 - %19.1 p<0.001). When skeletal system was divided into five subgroups , similarly, bone dansity area in the lesion was seen metastatic lesions more than multiple myeloma lesions. In conclusion, bone dansity area in the lesion is useable finding to distinguish lytic lesions of multiple myeloma from metastases. Besides, features like perilesional sclerosis , unsharply contour and heterogenous appearance are supportive findings that could be used differantiation of this two clinical conditions. Key words: Multiple myeloma, osteolytic metastasis, computed tomography