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 Staging of Renal Cell Carcinoma Using the Revised 1997 TNM Staging Criteria: In Comparison with the Previous One

PURPOSE: To assess the accuracy of preoperative CT staging of RCC and to compare the relationship between T stage and the incidence of metastasis on the basis of the old (1992) and the new (1997) UICC & AJCC tumor classification system. MATERIALS AND METHODS: In 112 cases of surgically resected RCC, the stagings of preoperative CT scans were de-termined retrospectively by two radiologists and were compared with the results of pathologic examinations. In 70 cases which had been followed up over three years after surgery, the incidence of metastasis at initial diagnosis and during the follow-up period was assessed. All cases were reconsidered, and using the old and the new TNM classification, the incidence of metastasis was compared. RESULTS: According to the old TNM classification, 5 cases (4%) were staged at T1, 73(65%) at T2, 21(19%) at T3a, 9(8%) at T3b, 0 at T3c, and 4(4%) at T4. Using the new TNM classification, we also staged 54 cases (48%) at T1 and 24(21%) at T2. Overall, using this new classification, CT correctly staged 79% of patients (88/112) overstaged 15%(17/112) and understaged 6%(7/112) . CT had a sensitivity of 84% and specificity of 91% in new T1 tumors, 71% and 95%, respectively, in new T2 tumors, 69% and 88% in T3a tumors, 78% and 98% in T3b tumors, and 75% and 99% in T4 tumors. CT had a sensitivity of 44% and a specificity of 99% in old T1 tumors, and 82% and 71%, respectively, in old T2 tumors. The incidence of metastasis in CT-staged (cT) tumors was 0% (0/4) in old cT1, 8% (3/39) in new cT1, 29% (4/14) in new cT2, 67% (6/9) in cT3a, and 75% (6/8) in cT3b. CONCLUSION: In the staging of T1 tumors, CT is more sensitive when the new TNM classification is used. Even though the cut off point between T1 and T2 tumors had been in creased from 2.5 to 7.0 cm, T1 tumors staged according to the new system did not show a significantly higher incidence of metastasis than those staged according to the old.

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.

CT findings of extramedullary hematopoiesis in the thorax, liver and kidneys, in a patient with idiopathic myelofibrosis

Extramedullary hematopoiesis occurring in multiple organs such as thorax, liver and both kidneys is an unusual condition. We report the CT findings of this condition with review of literature. The lesions consisted of intrathoracic paravertebral masses, focal intrahepatic mass and masses of both pelvocalyceal systems on CT scans.

CT findings of extramedullary hematopoiesis in the thorax, liver and kidneys, in a patient with idiopathic myelofibrosis

Extramedullary hematopoiesis occurring in multiple organs such as thorax, liver and both kidneys is an unusual condition. We report the CT findings of this condition with review of literature. The lesions consisted of intrathoracic paravertebral masses, focal intrahepatic mass and masses of both pelvocalyceal systems on CT scans.

Radiologic Findings of Renal Hemangioma: Report of Three Cases

Renal hemangioma is an uncommon benign tumor which usually causes painless or painful gross hematuria. Its preoperative diagnosis is extremely difficult or even impossible. We experienced three cases of renal hemangioma, located mainly at the pelvocalyceal junction or in the inner medulla. US demonstrated variable echogenecity, and CT revealed a lack of significant enhancement. Where there is gross hematuria in a young adult, especially when the renal mass located in the pelvocalyceal junction or inner medulla shows little enhancement on CT, renal heman-gioma should form part of the differential diagnosis.

CT Staging of Renal Pelvis Tumor

PURPOSE: To assess the value of computed tomography (CT) in the preoperative staging of transitional cellcarcinoma (TCC) of the renal pelvis. MATERIALS AND METHODS: We retrospectively evaluated the CT TNM staging of 38patients with TCC of the renal pelvis who had undergone preoperative abdominal CT examination between January 1990and January 1998. In CT staging for differentiation between early-stage (TO-2) and advanced-stage disease (T3-T4),three criteria were used, namely the presence or obliteration of the renal sinus fat layer, the smoothness orirregularity of margin between the tumor and renal parenchyma, and the presence or absence of hydronephrosisproximal to the tumor. CT staging was performed by two genitourinary radiologists blinded to the pathologicresults, and was compared with pathologic staging. RESULTS: Pathologic results revealed 19 cases of early stagedisease (TO=8, T1=9, T2=2) and 19 of advanced stage (T3=12, T4=7). Overall CT staging accuracy was 82%(31/38);fourcases were overstaged and three were understaged. In early-stage disease, sensitivity and specificity were 79%,and 84%, and in advanced stage disease were 83% and 80%. Three of four overstaged cases showed hydronephrosisproximal to the tumor. In the second CT staging, using proximal hydronephrosis of the tumor as a criterion forearly-stage disease, the sensitivity and specificity of early-stage disease were 95% and 75%, respectively, andthe specificity of advanced-stage disease was 95%. CONCLUSION: When hydronephrosis proximal to a tumor wasconsidered to be a sign of early stage disease, the CT staging of renal pelvic TCC was highly accurate.

Imaging Features of Rhabdoid Tumor of the Kidney in Children

PURPOSE: To evaluate the difference in radiologic features of rhabdoid tumor of the kidney (RTK) in children according to the location of the tumor within the kidney. MATERIALS AND METHODS: We retrospectively reviewed the radiologic findings of pathologically confirmed RTK in seven children (5 boys and 2 girls; age range, 6 months to 4 years 8 months; median, 18 months). All subjects underwent abdominal CT. We analyzed tumor location, size, and margin; renal hilar involvement, subcapsular hematoma, calcification, necrosis, and lymphadenopathy. RTK was classified according to the location of the tumor within the kidney: A tumor that mainly located in the central portion of the kidney with or without peripheral extension was described as type I, while one located at the periphery was type II. Imaging findings between the two types were compared. RESULTS: Tumor size varied from 3 cm to 12 cm. Tumor outlines were ill-defined in four cases but relatively well-defined in three. Four tumors (57 %) were type I. Hilar involvement was found in all four and a small subcapsular hematoma in one. Three tumors (43%) were type II, and in all three, large crescent-shaped subcapsular hematomas were found. CONCLUSION: Centrally located RTK showed hilar involvement with a small subcapsular hematoma, while in cases of peripherally located RTK, a large subcapsular hematoma was present. These findings may be helpful for the differential diagnosis of other pediatric renal tumors.

Imaging Features of Rhabdoid Tumor of the Kidney in Children

PURPOSE: To evaluate the difference in radiologic features of rhabdoid tumor of the kidney (RTK) in children according to the location of the tumor within the kidney. MATERIALS AND METHODS: We retrospectively reviewed the radiologic findings of pathologically confirmed RTK in seven children (5 boys and 2 girls; age range, 6 months to 4 years 8 months; median, 18 months). All subjects underwent abdominal CT. We analyzed tumor location, size, and margin; renal hilar involvement, subcapsular hematoma, calcification, necrosis, and lymphadenopathy. RTK was classified according to the location of the tumor within the kidney: A tumor that mainly located in the central portion of the kidney with or without peripheral extension was described as type I, while one located at the periphery was type II. Imaging findings between the two types were compared. RESULTS: Tumor size varied from 3 cm to 12 cm. Tumor outlines were ill-defined in four cases but relatively well-defined in three. Four tumors (57 %) were type I. Hilar involvement was found in all four and a small subcapsular hematoma in one. Three tumors (43%) were type II, and in all three, large crescent-shaped subcapsular hematomas were found. CONCLUSION: Centrally located RTK showed hilar involvement with a small subcapsular hematoma, while in cases of peripherally located RTK, a large subcapsular hematoma was present. These findings may be helpful for the differential diagnosis of other pediatric renal tumors.

Mucinous Cystadenoma of Renal Collecting Duct Origin: A Case Report

We report a case of mucinous epithelial tumor (mucinous cystadenoma) in the renal pelvis. This type of tumor shows a non-specific cystic mass, and sometimes has wall calcification, it very rarely originates in multi-potential renal pelvic epithelium. We report the imaging findings of the tumor and review the previous literature.

Nontraumatic Spontaneous Rupture of the Kidney: Etiology and CT Findings

PURPOSE: To evaluate the usefulness of CT scanning in determining the etiology of spontaneous rupture of the kidney. MATERIALS AND METHODS: We retrospectively analyzed the CT findings of spontaneous rupture of the kidney in eleven patients, Four were male and seven were female, and they were aged between 20 and 71 (mean, 46.6) years. Both pre- and post-contrast enhanced CT scanning was performed in all patients. RESULTS: Spontaneous renal rupture was induced in seven cases by neoplasms (three angiomyolipomas, three renal cell carcinomas, and one metastatic choriocarcinoma), in three cases by infection or inflammation (acute and chronic pyelonephritis, and renal abscess), and in one, by renal cyst. Common CT findings of rupture of the kidney were the accumulation of high density fluid in the perirenal and anterior pararenal space, and in homogeneous irregular low density of renal parenchyma and the rupture site. Angoimyolipoma showed fat and an angiomatous component in the lesion, while acute and chronic pyelonephrities revealed thinning of the renal parenchyma and an irregular renal outline. Renal cell carcinoma showed a dense soft tissue mass in the parenchyma. Well-defined, round low-density lesions were noted in the case of renal cyst and renal abscess. CONCLUSION: CT is very useful in diagnosing and determining the etiology of non-traumatic spontaneous rupture of the kidney and plays an important role in the evaluation of emergency cases.

Sarcomatoid Transitional Cell Carcinoma in the Kidney: A Case Report

Sarcomatoid transitional cell carcinoma is a rare malignant epithelial neoplasm arising at the bladder, in which the tumor cells assume a spindle shape. This tumor accounts for approximately 0.3% of all bladder malignancies and has been reported in the renal pelvis and ureter. We encountered a case of histopathologically proven sarcomatoid transitional cell carcinoma of the left kidney in a 76-year-old male. Abdominal CT scans showed a large heterogeneous mass of solid and cystic components, with mural calcification and hematoma in the upper pole of the left kidney.

CT Findings of Renal Parenchymal Infiltration in Pelvocalyceal Transitional Cell Carcinoma

PURPOSE: The purpose of this study was to evaluate the CT findings of renal parenchyma infiltrated by pelvocalyceal transitional cell carcinoma. MATERIALS AND METHODS: This study included 28 patients in whom transitional cell carcinoma was dignosed after nephrectomy. CT findings were analyzed for the presence or absence of renal parenchymal infiltration; diagnostic criteria for this included parenchymal inhomogeneous low attenuation, ill-defined margin between the mass and renal parenchyma, or focal calyceal dilatation. To detect renal parenchymal infiltration by transitional cell carcinoma, we evaluated the frequency, sensitivity and specificity of each CT finding. RESULTS: Pathologic reports showed that renal parenchymal infiltration had occurred in 17 of 28 patients, (60.7%) ; on CT scans, renal parenchymal infiltration was seen in 15 of these 28 (53.6%). It two patients who did not show CT findings of renal parenchymal infiltration, pathologic examination revealed parenchymal invasion. All 15 patients who showed renal infiltration on CT had parenchymal inhomogeneous low attenuation (sensitivity: 88.2%, specificity : 100%), 13 showed ill-defined margin of the mass (sensitivity : 76.5%, specificity : 100%), and six showed focal dilatation of the calyx (sensitivity : 35.3%, specificity : 100%). CONCLUSION: In patients with pelvocalyceal transitional cell carcinoma, CT findings of parenchymal inhomogeneous low attenuation, ill-defined margin of mass, and focal calyceal dilatation suggest renal parenchymal infiltration, and these findings may be helpful in preoperative prognosis.

Multiphasic spiral CT of renal masses: Comparison among phases following contrast injection

PURPOSE: To assess the utility of multiphasic spiral CT for characterizing renal masses. MATERIALS AND METHODS: The study included 36 patients (53 lesions) referred for the evaluation of renal masses suspected on the basis of the results of sonography or radiography. Spiral CT of the kidneys was performed prior to and following power injection of intravenous contrast material (Optiray-320). Postcontrast imaging data were obtained and analyzed during early and late corticomedullary (20-30-second delay), nephrographic (60-70-second delay), and excretory (5-minute delay) phases. During each phase, the ability to detect renal masses was evaluated, and the ability to diagnose these masses on routine and multiphasic CT was assessed. Routine precontrast and excretory phase CT studies were performed and the usefulness of each phase for the diagnosis of renal cell carcinoma (RCC) and transitional cell carcinoma (TCC) was evaluated. RESULTS: The rates for the detection of renal masses were as follows: 94.3% on precontrast scan, 93.8% during the early corticomedulolary phase (ECMP), 98.1% during the late corticomedullary phase (LCMP), 100% during the nephrographic phase (NP), and 98.1% during the excretory phase (EP). During both routine and multiphasic CT, diagnostic accuracy was 96.2%, though for differential diagnosis, multiphasic CT was more helpful than routine CT in 4/16 cases of RCC and 2/8 cases of TCC. The highest for lesion characterization, during the LCMP in RCC, and the LCMP and NP in TCC ; for evaluation of tumor margin during the EP in both RCC and TCC ; for delineation of the renal artery, during the LCMP in both RCC and TCC ; for delineating the renal vein, during the NP in RCC, and the LCMP in TCC. CONCLUSION: For the detection and correct diagnosis oflesions, multiphasic CT was not superior to routine CT, but for the characterization of RCC and TCC, the former was helpful. The most useful phase can differ according to the kind of renal mass, and so for characterization of the mass, the most appropriate phase must be selected.

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.

CT Findings of Renal Cell Carcinoma: Correlation with Nuclear Grading and Cell Type

PURPOSE: To evaluate the CT appearance of renal cell carcinoma and to correlate it with nuclear grading andcell type. MATERIALS AND METHODS: The size, outer margin and heterogeneity of inner texture of renal cell carcinomas in 86 patients were evaluated on CT scan and were correlated with nuclear grade and cell type. RESULTS: Tumors less than 5cm were of low grade in 28 of 31 patients, while those larger than 5cm were of low grade in 28 of 55 patients. The lesions which showed no or round protrusion with a sharp margin were of low grade in 26 of 28 patients, while those which showed an undulated or indistinct margin were of low grade in 30 of 58 patients. Lesions which showed a homogeneous solid appearance, focal low densities, or mostly cystic changes were of low grade in 23 of 26 patients, while those which showed multiple or confluent low densites were low grade in 33 of 60 patients. There was a significant difference in the distribution of nuclear grading between the groups. Differences in CT apperance according to cell type were not found. CONCLUSION: Differences in less than 5cm showing no or round protrusion with a sharp margin, homogeneous inner texture with solid appearance, and heterogeneous inner texture with cystic appearance or focal low densities on CT scan were thought to be the findings suggesting low nuclear grading.