Computed Tomography and Magnetic Resonance Imaging Findings and Differential Diagnosis of the Renal Oncocytoma

Objective: To discuss the imaging features of renal oncocytoma, and to improve the preoperative diagnostic accuracy. Methods: Radiology data of 16 renal oncocytoma patients were analyzed retrospectively. All the cases were confirmed by pathology. All patients underwent pre-contrast and multiple phase contrast scanning on multi-slice CT. The patients also underwent MRI examination. Results: All patients had solitary lesion, the location of oncocytoma were in right kidney (n = 9) and left kidney (n = 7). Round or round-like shape, clear boundary, protruding mass. Isodense or slightly higher density on CT pre-contrast scanning, among them, 2 cases developed into the renal sinus, 2 cases with calcification. 13 lesions showed obvious enhancement on the cortical phase, and on the medullary phase showed continuous enhancement. 4 lesions showed segmental enhancement inversion and central stellate scar was found in 8 lesions. Bleeding, necrosis, cystic change or fatty change was rare. 9 lesions showed tortuous expansion of the support vessel on the cortical phase, 6 lesions with invasion to the perirenal fat tissue. In our study, 3 samples of lesions underwent MR examination, which showed iso/hypo-intensity on T1WI. On T2WI, 1 lesion showed slightly lower signal, 2 lesion showed mixed signal. Clear pseudocapsule was revealed in MR imaging. Enhanced scan showed mild continuous enhancement. Conclusion: Most of the oncocytornas showed certain characteristic imaging, multiple phase contrast scanning are helpful in the accurate preoperative diagnosis.