Correlation Between Contrast Enhanced Abdominal Computerized Tomography Scan and Histopathology in Evaluation of Renal Masses

Abstract

Renal tumors are divided into benign and malignant. The most common malignant renal tumor is renal cell carcinoma (RCC) with a rising incidence of about 3% per year since 1975, RCC accounts for nearly 3% of all solid tumors in the body and 65% of all renal tumors. According to contrast enhancing computerized tomography (CECT), The enhancing masses are classified as solid or complex cystic, 85% percent of solid masses are malignant. Contrast medium rapidly redistributes from the vascular to the interstitial spaces of the organs, the more vascular the organ or pathologic mass the more enhanced one. Therefore, a solid, enhancing mass must be considered malignant until proved otherwise. The aim of this study is to evaluate the role of contrast enhanced CT scan in the assessment of renal masses and its correlation with the histopathological type. Over a period of eight months (from February 2013 to September 2013) 45 patients presented with renal masses (diagnosed by ultrasound) submitted to abdominal CECT scan, then the renal masses radiologicaly evaluated in the form of site, size, degree and pattern of enhancement, then the radiological findings were correlated with the postoperative specimen histopathological results. Different histopathological types of renal tumors have different degree and patterns of enhancement. Regarding the degree of enhancement: The enhancement in Hounsfield units in order of frequency are as follows: Conventional renal cell carcinoma (Clear cell carcinoma) (27HU). Chromophobe renal cell carcinoma (19 HU). Onchocytoma (18.5 HU). Wilms (16.66HU). Transitional cell carcinoma (9.75 HU). Angiomyolipoma (5.33 HU). According to the homogeneity of enhancement: There is difference between type of tumors and homogeneity of enhancement, as follows: Conventional renal cell carcinoma (clear cell carcinoma) have heterogeneous in 75% and homogenous in 25% of tumors. Chromophobe renal cell carcinoma, 50% have homogenous, while other 50% have heterogeneous pattern. Oncocytomas and Transitional cell carcinoma have 100% homogenous enhancement. Wilms tumors have 100% heterogeneous patterns. Angiomyolipomas have homogenous pattern in 66.7 % while heterogeneous enhancement seen in 33.3 %. In conclusion, contrast enhanced CT Scan is highly valuable in differentiating types of renal masses in correlation with histopathological results.