Renal papillary carcinoma: CT and MRI features.

Abstract

To describe the CT and MRI appearances of papillary renal cell carcinoma. Retrospective study of 102 papillary carcinomas in 79 patients, 81 tumors examined by CT and 56 by MRI. Tumor size, homogeneity and contrast enhancement were recorded. The most common presentation of papillary renal cell carcinoma was a small homogeneous hypovascular tumor both on CT and MRI. Eighty-nine percent of lesions were hypointense on T2 weighted images compared to the renal parenchyma. Seventeen percent of the lesions did not significantly enhance with contrast on CT. All of the lesions examined on MRI had a significant enhancement percentage. Calcifications were rare and only seen in 7% of cases (CT). The second most common presentation was a bulky necrotic tumor. In addition, atypical types of disease were found which were difficult to diagnose, including infiltrating tumors and tumors with a fatty component. A homogeneous hypovascular renal tumor which is hypointense on T2 weighted images should suggest a diagnosis of papillary carcinoma. Some papillary carcinomas do not enhance significantly on CT. MRI is then required to diagnose the renal tumor.