Renal oncocytoma: Image diagnostics and therapeutic aspects

The renal oncocytoma is a solid epithelial neoplasm with a generally benign course. The improved image diagnostics with the computerized tomography (C T) and magnetic resonance imaging (MRI) should today permit the identificat ion of these lesions preoperatively so that conservative rather than radica l surgery can be employed, especially in the presence of an early or incide ntal diagnosis, this latter being always more frequent today. Eighteen patients (9 women and 9 men) with renal oncocytoma are presented. The sizes of the lesions ranged from 1.5 to 12 cm and all were studied by m eans of ultrasonography, CT and MRI. The MRI was found to be superior to both the ultrasonography and the CT in identifying smaller than 5 cm lesions, presenting typical, homogeneous low- density images in the T1-weighted image sequences which appeared hyperinten se in the T2-weighted ones. The presence of a central scar or stellate arch itecture, the absence of hemorrhage and necrosis and the presence of a pseu docapsule are other elements to differentiate an oncocytoma from a renal ca rcinoma. These aspects are less characteristic in greater than 5 cm lesions , making the differential diagnosis more difficult. Twelve patients were submitted to a radical nephrectomy and 6 underwent enu cleation. The follow-up of the patients (6-74 months) showed a disease-free survival in 17, while one patient died of distant metastases. No local rec urrences were observed after conservative surgery which should be considere d the treatment of choice in cases of renal oncocytoma with lesions of less than 5 cm.