Ultrasonographic features of renal oncocytoma with histopathologic correlation

Abstract

To analyze the sonographic (US) features of renal oncocytoma and correlate them with histopathologic findings. The medical records of 12 patients with a histologic diagnosis of renal oncocytomas were reviewed. The location, size, shape, margin, echogenicity, homogeneity, and blood flow distribution of the lesions were analyzed, and the US features were compared with histopathologic findings. Oncocytomas appeared as solid, solitary, well-marginated, unencapsulated, fairly homogeneous renal cortical masses (n = 10), with regular shape, relatively isoechoic (n = 5) or slightly hyperechoic (n = 7) to the adjacent renal parenchyma, and an exophytic growth pattern was exhibited in most cases (n = 9). Two larger masses (≥9 cm) demonstrated a central stellate scar and a characteristic of spoke-wheel vascular pattern. The tumors with a low percentage of stroma (<20%) were associated with an echotexture isoechoic to renal parenchyma, whereas oncocytomas with a higher percentage of stroma (>20%) were slightly hyperechoic. Although the US features are not pathognomonic, their presence should alert to the possible diagnosis of renal oncocytoma.