Role of multi-detektor computed tomografy in the differation malign-benign solid neoplastik renal mass: Correlating with histopatholojical finding

Introduction and Aim: The aim of our study is to investigate the contribution of computed tomography in the differentiation of malignant and benign solid renal masses according to morphologic and enhancement criteria. Materials and methods: Patients who were admitted with a diagnosis of renal mass between 2007-2015, who had underwent Dynamic Multiphasic Contrast CT and had pathological reports were reviewed. Sixty-seven lesions found in 64 patients were radiologically evaluated and correlated with pathological reports. The parameters assessed in the study were patient age, gender, dimensions of the mass, lesional calcification and cystic necrotic degeneration, relation with neighboring organs , histopathological type, Fuhrman grade and lesional density scores found in precontrast-corticomedullary phase and nephrogram phases on CT, EKİ and GKİ, tumor/aorta and tumor/parenchyme density rates in KM and NG phases. Results: Of the 64 patients, 29 were males and 35 were females. A total of 67 lesions were found, of which 53 were malignant and 14 were benign. Pathologically, Furhman grading of only 26 RCC lesions out of 48 were available. The pathological typing of the lesions were as follows: 48 RCC (28 clear cell RCC, 20 non-clear cell RCC), 3 TCC, 1 Wilm's tumor, 1 lymphoma, 1 hydatic cyst, 4 pyelonephritis-abscess, 3 AML, 5 oncocytoma and 1 multiloculated nephroma. The benign lesions in our study were of small diameter and held contrast homogenously. As the diameter of the lesions increase, malignancy potential increases. In addition, these lesions are agressive and high stage tumors. Clear cell RCC holds contrast densely and heterogenously in the KM phase and shows wash-out in the following phases. The chromophobe type holds contrast moderately and the papillary type holds contrast weakly. In the differentiation of clear cell RCC from other subtypes, prekontrast , EKİ ve tm/ao ratio in the KM phases may be used. Precontrast and EKİ cut-off values have been found to be 26.5 HÜ and 45.5 HÜ, relatively. The tumor/aorta ratıo in the corticomedullary phase cut-off value of 0.295 may be used . Conclusion: Differentiation of malignant and benign lesions can be done by firstly looking at morphological characteristics. The most valuable parameter in subtyping of renal cell carcinomas is the degree of enhancement Clear cell RCC has the highest value among all subtypes of RCC in all phases in contrasted dynamic series. The parameter with the highest accuracy in differentiating the clear cell subtype from other subtypes is the precontrast phase density. Key Words: Multidetector Dynamic renal CT, differential diagnosis in malign-benign renal masses, histopathological subtypes, lesion density and morphological features