Collecting Duct Carcinoma of the Kidney Mimicking Invasive Transitional Cell Carcinoma: A Case Report

Approximately 100 cases of collecting duct carcinoma have been reported in the medical literature. We herein report on a case of collecting duct carcinoma of the kidney in a 75-year-old patient. The abdominal sonography depicted a relatively poorly defined 7X6 cm sized, isoechoic mass lesion, as compared to the normal parenchyma, at the left kidney lower pole and the affected kidney showed preservation of the reniform shape. CT revealed a heterogeneous poorly defined low-attenuation mass that was mainly located in the medulla with involvement of the cortex and the lower half of the renal pelvis. Retrograde ureteropyelography showed a filling defect at the lower renal pelvis and severe narrowing of the left proximal ureter. We initially thought this lesion was invasive transitional cell carcinoma. Subsequent surgery confirmed a collecting duct carcinoma.

Radiologic Differentiation Between Homogeneously Solid Renal Cell Carcinoma and Muscle-Predominant Renal Angiomyolipoma

PURPOSE: To compare the differential radiologic findings of renal cell carcinoma presenting as a homogeneous solid mass (HS-RCC) and muscle-predominant angiomyolipoma (MP-AML). MATERIALS AND METHODS: Nine of 76 surgically and pathologically proven RCCs presenting at CT or magnetic resonance (MR) imaging as a homogeneous solid mass, and four cases of MP-AML were included in this study. Echogenicity at sonography, attenuation at non-enhanced CT (NECT), the contour of the mass, signal intensities at T1- and T2-weighted MR imaging, the existence of a capsule, and the pattern and degree of enhancement at CT and MR imaging were retrospectively analyzed. RESULTS: Two of five HS-RCCs were isoechoic and three were hyperechoic. Two of three MP-AMLs, however, were isoechoic, and one was mixed echoic. All nine HS-RCCs were round or oval in shape, but three MPAMLs were lobulated and one was round. At NECT, seven of eight HS-RCCs were isodense and one was hypodense compared to surrounding normal renal parenchyme, but three MP-AMLs were hyperdense masses and one was isodense. At enhanced CT, HS-RCCs showed various degrees of homogeneous enhancement, but all MP-AMLs showed moderate homogeneous enhancement. All three MP-AMLs demonstrated heterogeneous hypointensity at T2-weighted MRI and homogeneous hypointensity at T1-weighted MRI. HS-RCCs showed various signal intensities at both T1- and T2-weighted MRI, and in five cases, heterogeneous high signal intensity at T2-weighted MRI. Capsules were observed in seven of nine HS-RCCs but not in any of the three MP-AMLs. At enhanced T1-weighted MRI, MP-AMLs showed mild to moderate enhancement, but HSRCCs showed mild, moderate, and strong enhancement in two, two, and five cases, respectively. CONCLUSION: Echogenicity, density at NECT, signal intensity at MR T2-WI, the contour of the mass, and the existence of a capsule are features which are useful in the differential diagnosis of HS-RCC and MP-AML.

CT and US Findings of Multilocular Cystic Renal Cell Carcinoma

OBJECTIVE: Multilocular cystic renal cell carcinoma (MCRCC) is a recently described variety of renal cell carcinoma with characteristic pathologic and clinical features. The purpose of this study was to analyze the imaging findings of MCRCCs. MATERIALS AND METHODS: Ten adult patients with pathologically proven unilateral MCRCC who underwent renal US and CT were included in this study. The radiologic findings were retrospectively evaluated for cystic content, wall, septum, nodularity, calcification and solid portion by three radiologists who established a consensus. Imaging and postnephrectomy pathologic findings were compared. RESULTS: All patients were adults (six males and four females) and their ages ranged from 33 to 68 years (mean, 46). On US and CT images, all tumors appeared as well-defined multilocular cystic masses composed of serous or complicated fluid. In all patients, unenhanced CT scans revealed hypodense cystic portions, and in four tumors, due to the presence of hemorrhage or gelatinous fluid, some hyperdense areas were also noted. In no tumor was an expansile solid nodule seen in the thin septa, and in only one was there dystrophic calcification in a septum. Small areas of solid portion constituting less than 10% of the entire lesion were found in six of the ten tumors, and these areas were slightly enhanced on enhanced CT scans. In all patients, imaging and pathologic findings correlated closely. CONCLUSION: On US and CT images, MCRCC appeared as a well-defined multilocular cystic mass with serous, proteinaceous or hemorrhagic fluid, with no expansile solid nodules in the thin septa, and sometimes with small slightly enhanced solid areas. Where radiologic examinations demonstrate a cystic renal mass of this kind in adult males, MCRCC should be included in the differential diagnosis.

CT and US Findings of Multilocular Cystic Renal Cell Carcinoma

OBJECTIVE: Multilocular cystic renal cell carcinoma (MCRCC) is a recently described variety of renal cell carcinoma with characteristic pathologic and clinical features. The purpose of this study was to analyze the imaging findings of MCRCCs. MATERIALS AND METHODS: Ten adult patients with pathologically proven unilateral MCRCC who underwent renal US and CT were included in this study. The radiologic findings were retrospectively evaluated for cystic content, wall, septum, nodularity, calcification and solid portion by three radiologists who established a consensus. Imaging and postnephrectomy pathologic findings were compared. RESULTS: All patients were adults (six males and four females) and their ages ranged from 33 to 68 years (mean, 46). On US and CT images, all tumors appeared as well-defined multilocular cystic masses composed of serous or complicated fluid. In all patients, unenhanced CT scans revealed hypodense cystic portions, and in four tumors, due to the presence of hemorrhage or gelatinous fluid, some hyperdense areas were also noted. In no tumor was an expansile solid nodule seen in the thin septa, and in only one was there dystrophic calcification in a septum. Small areas of solid portion constituting less than 10% of the entire lesion were found in six of the ten tumors, and these areas were slightly enhanced on enhanced CT scans. In all patients, imaging and pathologic findings correlated closely. CONCLUSION: On US and CT images, MCRCC appeared as a well-defined multilocular cystic mass with serous, proteinaceous or hemorrhagic fluid, with no expansile solid nodules in the thin septa, and sometimes with small slightly enhanced solid areas. Where radiologic examinations demonstrate a cystic renal mass of this kind in adult males, MCRCC should be included in the differential diagnosis.

Renal Cell Carcinoma in Adult Polycystic Kidney Disease: A Case Report

The authors report a case of a renal cell carcinoma occurring in an adult suffering from polycystic kidney disease and diagnosed by radiologic examination. The patient presented with palpable flank mass, hematuria and weight loss. Ultrasonography, CT, MRI and angiography were performed preoperetively. Although severe renal architectural distortion and destruction caused by polycystic disease had masked evidence of malignancy, this was diagnosed after examination of the solid component of the mass lesion, and its hypervascular character, as seen on the three types of radiologic image. Malignancy was confirmed through nephrectomy and pathological examination.