OBJECTIVE. Clear cell papillary renal cell carcinoma (RCC), an entity with strikingly indolent behavior, recently was added to the World Health Organization classification of renal tumors and represents the fourth most common histologic type of renal cell carcinoma. This article aims to describe the imaging features of clear cell papillary RCC along with its clinical and pathologic characteristics. MATERIALS AND METHODS. This retrospective study consisted of 27 patients with 44 clear cell papillary RCC tumors. The inclusion criteria were a pathologically proven clear cell papillary RCC and the availability of preoperative imaging including at least CT or MRI. Two experienced radiologists performed the imaging analysis independently. RESULTS. Patients (mean age, 62 years old) presented with renal failure in 26% of cases, and four had a tumor-predisposing disease. Multiple clear cell papillary RCC tumors occurred in 5 of the 27 patients. Two imaging patterns were recognizable. Solid clear cell papillary RCC (n = 23, 52%) presented as heterogeneous tumors with minor cystic changes (74%) and rarely exhibited calcifications (10%). All solid tumors showed hyperintensity on T2-weighted images compared with renal cortex and maximal enhancement on corticomedullary phase with a delayed washout. Cystic clear cell papillary RCC (n = 21, 48%) were classified as Bosniak IV (57%), III (33%), or IIF (10%), with a predominant unilocular pattern (76%). Pathologic stage according to TNM classification was mostly pT1a and low grade on nucleolar grade. All patients were alive at the date of last follow-up after treatment with no metastasis or recurrence. CONCLUSION. Clear cell papillary RCC exhibits two imaging patterns including cystic and solid in almost equal proportion. Imaging characteristics of solid clear cell papillary RCC including high signal T2 intensity and early arterial enhancement are unexpectedly distinct from papillary RCC and very similar to clear cell RCC.
One hundred eighty-seven native kidneys in 96 patients were examined with color Doppler ultrasound (US) to (a) determine the color Doppler US characteristics of renovascular disorders and (b) assess the value of color Doppler US in detection of such disorders. Correlative angiography or computed tomography was performed in 94 patients. The following renovascular disorders were found: renal artery (RA) stenosis (40 cases), RA thrombosis (13 cases), RA aneurysm (four cases), renal vein thrombosis (three cases), arteriovenous fistula (three cases), peripheral infarction (one case of bilateral infarcts), and distal occlusive disease (three cases). One case of aortal coarctation was also found. Color Doppler US failed to demonstrate the proximal main RA in 25% of cases (among 193 RAs total including supernumerary RAs). The sensitivity and specificity of color Doppler US for the detection of RA stenosis or thrombosis were 89% and 99%, respectively. Color Doppler US thus appears to be effective in the diagnosis of renovascular disease in native kidneys.
