Renal Parenchymal Invasion Research Articles

Upper tract transitional cell carcinoma: An array of imaging conundrum

We report a 38-year-old gentleman who presented with painless haematuria for 6-months duration. Contrast-enhanced CT renal revealed a large, calcified intrapelvic mass with calyceal extension confined within the right kidney with moderate pelvicalyceal dilatation but no evidence of synchronous lesion elsewhere. Histopathological analysis showed high grade urothelial carcinoma of the renal pelvis with invasion of renal parenchyma. Upper tract urothelial carcinoma (UTUC) which was once thought similar to urothelial carcinoma of the bladder (UCB), is increasingly being recognized as a different entity. However, heterogenous array of imaging manifestations of UTUC is also increasingly being encountered and pose diagnostic challenges though UTUC is not as prevalent as UCB which is easier to diagnose. Despite distinctive features against renal cell carcinoma (RCC), UTUC may mimic numerous other renal pathologies especially the benign ones hence imaging plays a pivotal role in ascertaining the diagnosis. This disease is usually treated with radical nephroureterectomy with superadded neoadjuvant chemotherapy for high-risk cases. Less invasive endoscopic resection is also offered in certain cases but stringent surveillance of the whole urinary tract as well as post-operative follow-up are mandatory.

The poor antitumor effect of pembrolizumab in advanced upper urothelial carcinoma with renal parenchymal invasion.

We investigated poor prognosticators in advanced or unresectable urothelial carcinoma, focusing on renal parenchymal invasion (RPI). This study included 48 bladder cancer (BC) and 67 upper tract urothelial carcinoma (UTUC) patients treated with pembrolizumab from December 2017 to September 2022 at Kobe University Hospital. Medical records were retrospectively reviewed for clinical characteristics, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Multivariate analyses were performed using the Cox proportional hazard regression model to identify parameters associated with either PFS or OS. Of 67 UTUC patients, 23 had RPI and 41 patients did not, while 3 cases could not be evaluated. Patients with RPI were predominantly elderly and had liver metastases. ORR for patients with RPI was 8.7%, while it was 19.5% for those without RPI. PFS was significantly shorter for patients with RPI compared with those without RPI. Patients with RPI had significantly shorter OS than those without RPI. On multivariate analysis, performance status (PS) ≥ 2, neutrophil-lymphocyte ratio (NLR) ≥ 3, C-reactive protein ≥0.3 mg/dL and RPI were independent prognostic factors for PFS. PS ≥ 2, NLR ≥ 3, visceral metastasis and RPI were independent prognostic factors for OS. UTUC patient OS was significantly shorter than BC patient OS, while no significant difference in PFS or OS was observed between BC patients and UTUC patients without RPI. RPI was a poor prognostic factor in advanced urothelial carcinoma treated with pembrolizumab, possibly resulting in a poorer prognosis for UTUC compared with BC.

Reclassifying pT3 renal pelvic urothelial carcinoma with renal parenchyma invasion to pT2 improves correlation with overall survival

The American Joint Cancer Committee pT categorization in renal pelvic carcinoma defines pT3 as invasion of renal parenchyma, invasion of peripelvic fat, or both. However, survival heterogeneity within the pT3 category has been demonstrated. This investigation sought to compare survival between pT categories of renal pelvic urothelial carcinoma and identify modifications to improve correlation with survival. Pathology reports from nephroureterectomies performed at our institution from 2010 to 2019 were analyzed to identify primary renal pelvic urothelial carcinoma (n=146). Tumors were stratified based on pT, pN, and invasion of renal parenchyma vs invasion of peripelvic fat with or without renal parenchyma invasion. Kaplan-Meier survival curves and Cox regression multivariate analysis were used to compare overall survival between groups. Similar survival curves were observed for pT2 and pT3 tumors. Multivariate analysis confirmed overlapping hazard ratios (HRs) for pT2 (HR=2.64, 95% confidence interval [CI] = 0.69, 10.06)and pT3 (HR=4.42, 95% CI = 2.08, 9.37). pT3 tumors with peripelvic fat invasion, regardless of renal parenchyma involvement, had a 3.3-fold worse overall survival than pT3 tumors with only renal parenchyma involvement. Additionally, pT3 tumors with only renal parenchyma invasion had similar survival compared to pT2, while pT3 tumors with peripelvic fat invasion had worse overall survival (p=0.00091). Reclassifying renal parenchyma invasion as pT2 yielded greater survival curve separation and greater difference in HRs. For renal pelvic urothelial carcinoma, modifying the pT3 category to only include tumors with peripelvic fat invasion and expanding the pT2 category to include renal parenchyma invasion may improve pT correlation with overall survival.

Is Preoperative Magnetic Resonance Imaging in a Daily Clinical Setting Useful to Evaluate Tumor Invasion Beyond the Pseudocapsule in Renal Cell Carcinoma?

We wanted to clarify whether preoperative magnetic resonance imaging (MRI) in the clinical setting can evaluate the pathologic pseudocapsule (PC) morphology with high accuracy in renal cell carcinoma (RCC). We retrospectively analyzed 34 consecutive patients who underwent MRI (1.5 or 3.0T, 5 mm slices) prior to partial nephrectomy (PN) for RCC at our institution between January 2010 and December 2019. First, the correlation between PC morphology (complete or incomplete) and tumor infiltration to the renal parenchyma was examined as pathologic validation. Second, the concordance rate of PC morphology between pathologic tissue and preoperative MRI was evaluated as radiologic validation. Third, risk factor for renal parenchymal invasion in RCC was analyzed. In the pathologic validation, parenchymal invasion rates were 11% and 28% in the "complete PC" and "incomplete PC" groups, respectively. In the radiologic validation, pathological PC morphology could be diagnosed on preoperative MRI in 17 patients (50.0%). "None PC" on MRI had the lowest positive predictive value (PPV) (0%), "partial PC" on MRI had a good PPV (76.5%), "complete PC" on MRI had a relatively low PPV (33.3%). Unfortunately, these data were insufficient for diagnostic accuracy. As risk factor for renal parenchymal invasion in RCC, only pathologic subtype (non-clear cell) was found to have significant differences in the multivariate analysis. The results of this study suggest that renal tumors with pathologically incomplete PC have a high possibility of renal parenchymal invasion. However, it is currently difficult to accurately evaluate pathologic PC morphology by preoperative MRI in the clinical setting.

Renal Tumor Invasion Depth and Diameter are the Two Most Accurate Anatomical Features Regarding the Choice of Radical Versus Partial Nephrectomy

To evaluate simple tumor characteristics (renal tumor diameter and parenchymal invasion depth) compared with more complex classifications, that is, Renal Tumor Invasion Index (RTII) and Preoperative Aspects and Dimensions Used for an Anatomical classification, in predicting the type of nephrectomy (radical vs partial) performed. A total of 915 patients who had undergone either partial nephrectomy ( n = 388, 42%) or radical nephrectomy ( n = 527, 58%) were identified from the Helsinki University Hospital kidney tumor database between 1 January 2006 and 31 December 2014. Tumor maximum diameter and depth of invasion into the parenchyma were estimated from computed tomography or magnetic resonance imaging images and compared with Preoperative Aspects and Dimensions Used for an Anatomical and Renal Tumor Invasion Index. Logistic regression and receiver operating curves were used to compare the parameters at predicting the type of nephrectomy. All the anatomical variables of receiver operating curve/area under the curve analyses were significant predictors for the type of nephrectomy. Parenchymal invasion (area under the curve 0.91; 95% confidence interval, 0.89-0.93), RTII (area under the curve 0.91; 95% confidence interval, 0.89-0.93), and diameter (area under the curve 0.91; 95% confidence interval, 0.89-0.93) performed significantly better than Preoperative Aspects and Dimensions Used for an Anatomical classification (area under the curve 0.88; 95% confidence interval, 0.85-0.89). In multivariable analysis, invasion depth was the best predictor of nephrectomy type (percentage correct, 85.6%). Addition of one anatomic parameter into the model of non-anatomical cofactors improved the accuracy of the model significantly, but the addition of more parameters did not. Parenchymal invasion depth and tumor diameter are the most accurate anatomical features for predicting the nephrectomy type. All potential anatomical classification systems should be tested against these two simple characteristics.

Clinical and prognostic factors for renal parenchymal, pelvis, and ureter cancers in SEER registries: collaborative stage data collection system, version 2.

The American Joint Committee on Cancer's (AJCC) 7th edition cancer staging manual reflects recent changes in cancer care practices. This report assesses changes from the AJCC 6th to the AJCC 7th edition stage distributions and the quality of site-specific factors (SSFs). Incidence data for renal parenchyma and pelvis and ureter cancers from 18 Surveillance, Epidemiology, and End Results (SEER) registries were examined, including staging trends during 2004-2010, stage distribution changes between the AJCC 6th and 7th editions, and SSF completeness for cases diagnosed in 2010. From 2004 to 2010, the percentage of stage I renal parenchyma cancers increased from 50% to 58%, whereas stage IV and unknown stage cases decreased (18% to 15%, and 10% to 6%, respectively). During this period, the percentage of stage 0a renal pelvis and ureter cancers increased from 21% to 25%, and stage IV and unknown stage tumors decreased (20% to 18%, and 7% to 5%, respectively). Stage distributions under the AJCC 6th and 7th editions were about the same. For renal parenchymal cancers, 71%-90% of cases had known values for 6 required SSFs. For renal pelvis and ureter cancers, 74% of cases were coded as known for SSF1 (WHO/ISUP grade) and 47% as known for SSF2 (depth of renal parenchymal invasion). SSF values were known for larger proportions of cases with reported resections. Stage distributions between the AJCC 6th and 7th editions were similar. SSFs were known for more than two-thirds of cases, providing more detail in the SEER database relevant to prognosis.

Primary carcinoma of renal calyx

Renal calyx carcinoma (RCXC) may mimic collecting duct carcinoma (CDC) or urothelial carcinoma (UC) of the renal pelvis. RCXC is distinguished from CDC and UC of the renal pelvis as having the tumor epicenter in the renal calyx, with limited involvement of the surrounding renal pelvis surface urothelium. In this study, we summarize our experience with this entity.Ten cases of RCXC, including 9 cases with urothelial differentiation (RCXC-UC) and 1 case with salivary gland-type differentiation (RCXC-SC), were identified. Ten consecutive cases of UC were selected for comparison, with extensive renal pelvis involvement and with secondary renal parenchymal invasion. Two cases of collecting duct carcinoma (CDC) were also examined. Immunohistochemistry (IHC) was performed on representative tissue blocks for PAX8, PAX2, CK5, CK7, CK20, p63, GATA3, AMACR, RCC, CD10, vimentin, S100, and MSA.The 10 cases of RCXC (M:F=4:6, ages: 62–91 years, mean: 76) presented with renal masses of 3–6cm. Ureteroscopic studies and renal pelvic washings showed atypical/malignant cells in three cases. Seven patients were treated with nephrectomy followed by radiation±chemotherapy, and all cases developed metastases to lymph nodes or liver/lung/bone.In all 7 cases with nephrectomy, there was extensive renal parenchymal involvement with infiltrating borders and diffuse spread along collecting ducts. Six RCXC-UC contained focal squamous differentiation. The RCXC-SC displayed features of adenoid cystic and basaloid features. In situ UC, with or without papillary components, was identified in the calyces in all 7 nephrectomy cases with remaining renal pelvis harboring small tumor burden in 5 cases, and no tumor in another 2 cases. Of the three cases without nephrectomy, no tumor in the renal pelvis could be visualized with endoscopy, however one case was associated with UC of the urinary bladder. Of 10 control UC cases, tumor was limited to the tip of renal papilla in 7 cases, extensive in 3 cases, and with no extension into the collecting ducts. RCXC-UC were all positive for p63, CK5, CK7, and PAX2, with all negative for RCC. PAX8 (70% positive) and GATA3 (50% positive) reactivity was variable. The 10 UC cases shared IHC properties with RCXC-UC but frequent negativity for PAX8 and positivity for GATA3.RCXC is an aggressive neoplasm with high risk of metastases. Similar to CDC, it is located in the renal papilla and rarely with clinically visible renal pelvis tumor or ureteral urine positive for tumor cells. Unlike CDC and non-calyceal UC, RCXC shows predominantly urothelial and squamous differentiation and is associated with an in situ component of adjacent renal calyces. By IHC, RCXC exhibited features intermediate between UC and CDC with decreased or negative immunoreactivity for PAX8 and GATA.

An Unusual Case of Renal Failure Due to Solitary Plasmacytoma: Parenchymal Invasion of the Kidney

Solitary extramedullary plasmacytoma (EMP) is a rare plasma cell disorder mostly involving the upper airway; however, retroperitoneal infiltration is very rare. Kidney injury associated with EMP is exceptionally rare with only anecdotal reports. Herein we report a case of retroperitoneal EMP causing renal failure by the way of direct renal parenchymal infiltration. Renal parenchymal invasion should be considered in aggressive and refractory plasma cell dyscrasias with unexplained renal failure.

A noninvasive renal fungus ball caused byRhizopus– a previously unreported manifestation of zygomycosis

We describe the first reported case of renal zygomycosis presenting as an isolated fungus ball (bezoar) without renal parenchymal invasion. Since all previous descriptions of renal involvement have discussed tissue invasion, our case is unique in that the infection was confined solely in the renal pelvis and extended to the distal ureter without signs of contiguous renal infection. Our patient later developed renal insufficiency while receiving amphotericin B Lipid Complex (ABLC). The therapy was changed to posaconazole with subsequent clinical, mycologic, and radiographic improvement and the patient has remained free of recurrence 5 years after diagnosis.

Imaging features of helical computed tomography suggesting advanced urothelial carcinoma arising from the pelvocalyceal system

Urothelial carcinoma is the most common malignant tumor arising from the pelvocalyceal system. Helical computed tomography (CT) is probably the best preoperative-stage modality for the determination of treatment plan and prognosis. To obtain helical CT imaging features suggesting advanced pelvocalyceal urothelial carcinoma. Preoperative CT images in 44 patients with pelvocalyceal urothelial carcinoma were retrospectively reviewed and correlated with the pathological examination to determine imaging features suggesting stage III or IV of the disease. Pathological stages revealed stage I in 16, stage II in three, stage III in 17, and stage IV in eight patients. Seven patients had metastatic lymph nodes. CT imaging showed that renal parenchymal invasion, sinus fat invasion, and lymph node metastasis were highly suggestive of advanced urothelial cell carcinoma (P<0.05). Helical CT sensitivity, specificity, and accuracy for advanced pelvocalyceal urothelial carcinoma were 76% (19/25), 84% (16/19), and 80% (35/44), respectively. Preoperative helical CT may suggest imaging features of advanced urothelial carcinoma, influencing treatment plan and patient prognosis, even though its accuracy is not so high.

Prognostic Impact of Peripelvic Fat Invasion in pT3 Renal Pelvic Transitional Cell Carcinoma

Renal pelvic transitional cell carcinoma (TCC), which invades beyond muscularis into peripelvic fat or the renal parenchyma, is diagnosed as stage pT3 despite its structural complexity. We evaluated the prognostic impact of peripelvic fat invasion in pT3 renal pelvic TCC. Between 1986 and 2004, the medical records on 128 patients who were surgically treated for renal pelvic TCC were retrospectively reviewed. Sixty patients with pT3 disease were eligible for the main analysis. The prognostic impact of various clinicopathological factors was analyzed using univariate and multivariate analyses. On univariate analysis, sex, age, concomitant bladder tumors, concomitant ureter tumors, lymphadenectomy, adjuvant chemotherapy, tumor grade, multiplicity, renal parenchymal invasion, and carcinoma in situ did not influence the disease-specific survival (p>0.05). By contrast, peripelvic fat invasion, lymph node invasion, and lymphovascular invasion were each significantly associated with disease-specific survival (p<0.05). Multivariate analysis showed that peripelvic fat invasion (p=0.012) and lymph node invasion (p=0.004) were independent prognostic factors. In conclusion, peripelvic fat invasion is a strong prognostic factor in pT3 renal pelvic TCC. Thus, systemic adjuvant therapy should be considered in the presence of peripelvic fat invasion, even if the lymph nodes are not involved.

A proposal for a novel staging system in renal pelvicaliceal urothelial carcinomas

Renal caliceal urothelial carcinomas, which have characteristic microanatomies in which the tumor directly interfaces to the renal parenchyma without intervening muscle propria, are often overstaged using the existing staging system. Relying on our analysis of 150 renal caliceal and/or pelvic urothelial carcinomas, we propose a novel staging scheme based on the extent of invasion relative to the corticomedullary junction (CMJ). Tumors were classified as category pT2 when renal parenchymal invasion was present within the CMJ and where the renal papillae and medulla were dominant. Tumors going over the CMJ were classified as pT3 with the proposed new scheme. It is very important to exclude pagetoid spread along the collecting ducts/ducts of Bellini to evaluate true invasion into the renal parenchyma. Using this revised staging scheme, 38.5% of tumors that were previously classified as pT3 were reclassified into the pT2 or pT1 groups. On multivariate Cox proportional hazard regression analysis, the extent of CMJ invasion and peripelvic fat invasion were the most significant prognostic indicators (P < .001, HR, 9.308; P = .016, HR, 2.538, respectively). In the new scheme, pT3 tumors showed a tendency to be classified toward the pT4 stage, whereas pT2 tumors were classified closer to the pT1 stage than to the pT3 (pT3 vs pT4, P = .0127; pT3 vs pT2, P < .0001). Renal parenchymal invasion beyond the CMJ has a strong prognostic impact for renal caliceal carcinomas. Using this new staging scheme, we can more precisely evaluate the level of tumor invasion.

Spectrum of US and CT findings in renal neoplasms with pathologic correlation

Objective: The purpose of this study was to characterize the image morphology of renal neoplasms on US (including CDFI) and CT and to stage these tumors and correlate the imaging findings with operative and/or histopathological findings. Materials and methods: a total of 50 patients were studied. These included renal cell carcinoma (n=38), angiomyolipoma (n=5), renal metastases (n=3), oncocytoma (n=1), transitional cell carcinoma (n=1), multilocular cystic nephroma (n=1) and nephroblastomatosis with Wilms tumour (n=1). All patients were evaluated by US and CT. Imaging finding were correlated with both operative and histopathological findings in 31 patients. Diagnosis was confirmed by percutaneous biopsy in 14 patients. In 5 patients final diagnosis was made on classical imaging features. Results : Most renal cell carcinomas had a solid appearance. On US, the most common appearance of RCC was predominantly isoechoic to normal renal parenchyma (78%) followed by hypo & hyperechoic lesions. Only 1 patient had cystic RCC. Solid renal cell carcinomas showed presence of peripheral and intralesional vascularity. The peak systolic Doppler frequency shift ranged from 0.5 KHz to 3.6 KHz. On CT, most of the lesions of RCC were heterogeneous in attenuation with inhomogeneous contrast enhancement less than that of normal renal parenchyma. Calcification was seen in 51%, necrosis in 94%, and haemorrhage in 20% lesions of RCC. Cystic RCC had thick walls, internal septations and solid components, all showing enhancement. Most of the angiomyolipomas (n=4) were homogenously hyperechoic on US, showed peripheral vascularity with peak systolic Doppler frequency shift less than 2.5 kHz. On CT, AML most commonly appeared as well defined, heterogeneous mass lesions showing internal fat density and variable contrast enhancement. Metastatic renal lesions were seen as small, homogenously hypoechoic on US, hypo to isodense on CT and showed minimal or no contrast enhancement. One case of oncocytoma showed a well defined, homogenous mass with central echogenic stellate scar and calcification on US. CT showed homogenous contrast enhancement with central hypodense stellate scar. TCC appeared as an intermediate echogenic mass on US, located in the dilated renal pelvis and extending into the upper ureter. On CT the mass was located centrally having density greater than that of urine, showing minimal contrast enhancement with centrifugal extension and invasion of renal parenchyma. Multilocular cystic nephroma was seen as a well-defined lesion with multiple cystic spaces, separated by septae which were echogenic on US and showed mild to moderate enhancement on CT. Conclusion: US and CT show many of the key imaging features used to characterize most of the renal neoplasms. However, some lesions remain indeterminate and require percutaneous biopsy to confirm the diagnosis.

Renal Oncocytoma: A Reappraisal of Morphologic Features With Clinicopathologic Findings in 80 Cases

Renal oncocytoma has several features that overlap with other renal neoplasms with a preponderance of granular cytoplasm, such as chromophobe, granular, and papillary renal cell carcinomas. Lack of knowledge of this entire spectrum of eosinophilic renal cell neoplasms has led to several misconceptions in the literature regarding renal oncocytoma. These include the of oncocytomas, metastatic oncocytomas, and the impression that renal oncocytoma is usually low grade and lacks prominent nucleoli. In order to further characterize the histologic features and embelLish diagnostic criteria, we evaluated 93 tumors from 80 patients. Four tumors were bilateral and two were multifocal. The mean age was 67.2 years (32-89 years), men were more commonly affected (3.1:1), and 82.7% tumors were incidental findings. Grossly, the tumors were mahogany brown, lacked necrosis, and averaged 4.4 cm in size (range 0.6-15 cm). Histologically, renal oncocytoma was composed of an exclusive or predominant component of acidophilic cells with three architectural patterns of disposition: (a) The classic (57.5%), composed of a characteristic nested or organoid arrangement of cells, each surrounded by a distinct reticulin framework; (b) a pattern (6.3%) with numerous closely packed cystically dilated tubular structures; and (c) mixed pattern (36.2%), which had both the organoid and tubulocystic patterns. A gross or microscopic scar was noted in 53.8% cases, and histologically a distinctive myxoid and/or hyalinized stroma separated nests of cells. Generally, the nuclei of renal oncocytoma were round with uniform nuclear contours. Nearly half of the tumors had prominent nucleoli (42.5% had prominent nucleoli equivalent to Fuhrman's grade III or IV). Pleomorphism was absent in 50% of cases but was conspicuous in 12.5% of cases including foci of bizarre cells. Other atypical features included perinephric fat involvement (11.3%), renal parenchymal invasion not associated with desmoplasia (10%), and hemorrhage (31.3%). Renal oncocytoma by definition lacks areas of clear cell carcinoma, significant lesional necrosis, or conspicuous papillary formations. Ancillary features noted included normal-appearing renal tubules within the lesion (15%), intranuclear holes (20%), psammoma bodies (7.5%), and foam cells (7.5%). 15% of tumors were locally excised, and 85% resulted in radical nephrectomy. Mean follow-up of 7.6 years (range 15-200 months) showed no evidence of recurrence, metastasis, or death due to tumor. In conclusion, renal oncocytoma, herein described, is a benign neoplasm and therefore does not merit a nuclear grading scheme. It has unique histologic features including an organoid and tubulocystic architecture, myxoid or hyalinized stroma, and occasionally some atypical findings including nuclear pleomorphism, prominent nucleoli, and adjacent renal parenchymal and perinephric fat involvement.

Conventional CT Signs in Staging Transitional Cell Tumors of the Upper Urinary Tract

Objectives: To determine conventional computed tomography (CT) signs in the diagnosis and staging of upper urinary tract tumors (UUTTs). Methods: Retrospective study was made of the CTs of 82 patients diagnosed with UUTTs. Nine CT signs were defined and compared with the pathology of the surgical specimen. A χ² test was used for statistical analyses. Results: We reviewed the CTs of 93 UUTTs in 82 patients, of which 36% were invasive and 12% had positive lymph nodes. Renal parenchymal invasion was found in 82% of high-grade and in 18% of low-grade tumors (p = 0.001). 94% of the tumors with signs of renal parenchymal invasion were invasive (p < 0.001), as well as 88% of those appearing as renal masses (p = 0.005), with a global sensitivity of 64% and specificity of 97%. The CT sensitivity and specificity of detecting infiltration of the ureter was 67 and 77%, respectively, and no sign was statistically significant. The detection of lymph node involvement had a sensitivity of 87.5% and a specificity of 98%. Conclusions: CT offers good sensitivity (87.5%) and specificity (98%) in the detection of lymph node involvement, and 64% sensitivity and 97% specificity for the detection of renal tumor invasion.

Nephrectomy during operative management of retroperitoneal sarcoma.

Complete resection of a retroperitoneal sarcoma often requires removal of adjacent organs. In this study we evaluated the role of nephrectomy during operation for retroperitoneal sarcoma. Between July 1982 and July 1995, 75 of the 371 (20%) patients who underwent resection of retroperitoneal sarcoma at MSKCC underwent concommitant nephrectomy. Data concerning the reasons for nephrectomy, degree of sarcomatous renal involvement, and survival were retrospectively analyzed. Fifty-four patients (72%) underwent nephrectomy during the initial resection, and 21 (28%) during a resection of a recurrent or persistent tumor. The most common reason for nephrectomy was total encasement by sarcoma (n = 40; 53%), followed by dense adherence of the tumor to the kidney (n = 21; 28%), and the direct invasion of the kidney by tumor (n = 2; 3%). Pathology demonstrated an absence of kidney invasion in the majority of cases (55 of 75; 73%). Renal capsular invasion was present in 11 of 75 (15%), renal parenchymal invasion in 7 of 75 (9%), and renal vein invasion in 2 of 75 (3%) of cases. There were no significant differences in survival based on degree of sarcoma involvement of the kidney, tumor grade, or whether the resection was for primary or recurrent disease. The 53 patients who underwent a complete gross resection of all tumor had a significantly improved long-term survival compared to the 20 patients who did not (50% versus 20% DFS at 5 years, respectively; p < 0.001). Decisions for concomitant nephrectomy during resection of retroperitoneal sarcoma should be based on whether this maneuver will provide a complete resection of all gross tumor, in which case the long-term disease-free survival of 50% is comparable to the reported 5-year survival of all patients with retroperitoneal sarcoma who are completely resected.

Renal oncocytoma: a reappraisal of morphologic features with clinicopathologic findings in 80 cases.

Renal oncocytoma has several features that overlap with other renal neoplasms with a preponderance of granular cytoplasm, such as chromophobe, granular, and papillary renal cell carcinomas. Lack of knowledge of this entire spectrum of eosinophilic renal cell neoplasms has led to several misconceptions in the literature regarding renal oncocytoma. These include the "grading of oncocytomas," "metastatic oncocytomas," and the impression that renal oncocytoma is usually low grade and lacks prominent nucleoli. In order to further characterize the histologic features and embelLish diagnostic criteria, we evaluated 93 tumors from 80 patients. Four tumors were bilateral and two were multifocal. The mean age was 67.2 years (32-89 years), men were more commonly affected (3.1:1), and 82.7% tumors were incidental findings. Grossly, the tumors were mahogany brown, lacked necrosis, and averaged 4.4 cm in size (range 0.6-15 cm). Histologically, renal oncocytoma was composed of an exclusive or predominant component of acidophilic cells with three architectural patterns of disposition: (a) The "classic" pattern (57.5%), composed of a characteristic nested or organoid arrangement of cells, each surrounded by a distinct reticulin framework; (b) a "tubulocystic pattern" (6.3%) with numerous closely packed cystically dilated tubular structures; and (c) "mixed pattern" (36.2%), which had both the organoid and tubulocystic patterns. A gross or microscopic scar was noted in 53.8% cases, and histologically a distinctive myxoid and/or hyalinized stroma separated nests of cells. Generally, the nuclei of renal oncocytoma were round with uniform nuclear contours. Nearly half of the tumors had prominent nucleoli (42.5% had prominent nucleoli equivalent to Fuhrman's grade III or IV). Pleomorphism was absent in 50% of cases but was conspicuous in 12.5% of cases including foci of bizarre cells. Other atypical features included perinephric fat involvement (11.3%), renal parenchymal invasion not associated with desmoplasia (10%), and hemorrhage (31.3%). Renal oncocytoma by definition lacks areas of clear cell carcinoma, significant lesional necrosis, or conspicuous papillary formations. Ancillary features noted included normal-appearing renal tubules within the lesion (15%), intranuclear holes (20%), psammoma bodies (7.5%), and foam cells (7.5%). 15% of tumors were locally excised, and 85% resulted in radical nephrectomy. Mean follow-up of 7.6 years (range 15-200 months) showed no evidence of recurrence, metastasis, or death due to tumor. In conclusion, renal oncocytoma, herein described, is a benign neoplasm and therefore does not merit a nuclear grading scheme. It has unique histologic features including an organoid and tubulocystic architecture, myxoid or hyalinized stroma, and occasionally some atypical findings including nuclear pleomorphism, prominent nucleoli, and adjacent renal parenchymal and perinephric fat involvement.

Transitional cell carcinoma of the upper urinary tract: staging by MRI.

This study evaluates the ability of MRI to stage transitional cell carcinoma of the upper urinary tract. Nine patients who had transitional cell carcinoma of the upper urinary tract detected by other imaging modalities underwent MRI examination at 1.5 T. Imaging included pre- and postgadolinium-DTPA T1-weighted images (9 patients) pre- and postgadolinium chelate T1-weighted fat-suppressed spin echo (7 patients). Postcontrast images were acquired prior to the presence of gadolinium within the collecting system (< 2 min postcontrast), intermediate (2.5-8 min), and late (> 10 min) postcontrast. Images were prospectively interpreted and lesion staging was determined. Correlation with histopathology was obtained in all cases. Transitional cell cancers were demonstrated in 9/9 patients, and tumors ranged in size from 2 to 8 cm (mean = 3.8 cm) in one dimension. Correct tumor staging was performed in 8/9 patients. The staging error in one case occurred because direct tumor extension into the renal parenchyma was not detected. The results of this preliminary study show that MRI stages transitional cell cancers relatively well; however, MRI is not able to detect superficial invasion of renal parenchyma.

Intraductal Tumor Involvement and Renal Parenchymal Invasion of Transitional Cell Carcinoma in the Renal Pelvis

Surgical specimens obtained from 21 patients with renal pelvic cancer, in which the tumor was located on the side of the renal parenchyma, were reviewed with special reference to tumor involvement with renal collecting ducts and/or renal parenchyma. Four distinct entities were found: 1) 4 tumors that involved the collecting ducts without invasion of renal parenchyma, 2) 4 tumors that involved the collecting ducts with microscopic invasion of renal parenchyma, 3) 5 tumors that invaded the renal parenchyma by less than 5 mm. and were microscopically identified as being without ductal involvement and 4) 6 tumors that exhibited extensive renal parenchymal invasion. The patients with intraductal tumors had good prognosis as did those with microscopic invasion except for 1 who died of lymph nodes metastases. Conversely, 6 patients with extensive invasion had a poor prognosis, 5 (88%) of whom died of recurrent tumor or distant metastases. The differences in these 4 entities may be important, especially if large numbers of patients are examined, and they may ultimately be shown to have a different prognosis.

Neuroblastoma invading the kidney

Renal invasion by neuroblastoma is probably more common than is generally recognized. In this study, the incidence of renal parenchymal tumor invasion was 20.4% (10 patients) among 49 cases of abdominal neuroblastoma. Generally, the renoinfiltrative neuroblastomas were extensive and had unfavorable histological features as well as lymph node involvement; they were either stage III or IV. Tumor invasion occurred by direct penetration through the renal capsule and/or lymphatic perivascular spread. Imaging studies had 100% sensitivity and 94.9% specificity for detecting renal invasion of neuroblastoma. Surgery/pathology was the standard of reference. Two instances of misdiagnoses of renal invasion were attributed to inadequate resolution of older computed tomography films, partial volume effects, and renal distortion by tumor compression.