Diagnosis and classification of renal cell carcinoma

Magnetic Resonance Imaging Virtual Biopsy of Common Solid Renal Masses-A Pictorial Review

ABSTRACT

The expanded application of radiologic imaging resulted in an increased incidence of renal masses in the recent decade. Clinically, it is difficult to determine the malignant potential of the renal masses, thus resulting in complex management. Image-guided biopsies are the ongoing standard of care to identify molecular variance but are limited by tumor accessibility and heterogeneity. With the evolving importance of individualized cancer therapies, radiomics has displayed promising results in the identification of tumoral mutation status on routine imaging. This article discusses how magnetic resonance imaging features can guide a radiologist toward identifying renal mass characteristics.

Role of diffusion-weighted MRI for prediction of regional lymph node positivity in radiologically organ-confined renal tumour: a prospective study

Background

Lymph node metastasis is one of the major factors that decide the prognosis of renal cell carcinoma. Presently, lymphadenectomy is only accepted as the most precise and dependable staging method to detect lymph node invasion; still, its therapeutic value for renal cell carcinoma is controversial. Diffusion-weighted magnetic resonance imaging along with its apparent diffusion coefficient value has already shown great value as a non-invasive modality to detect early microstructural changes in various human tumours. The present study is done to know the role of DWMRI in determining regional lymph node positivity in radiologically organ-confined renal cell carcinoma.

Methods

In this prospective study, we measured the ADC value of renal mass and regional lymph node in patient of RCC. ADC value < 1.25 is taken as cut-off to determine lymph node involvement. A malignant lymph node was confirmed by histopathology postoperatively. After that, we analysed the data retrospectively and studied the association between cut-off ADC value and lymph node positivity.

Results

Total 44 patients of RCC were evaluated in the study. Out of 44 patients, lymph node was found to be malignant on histopathology in 25 (56.8%) patients, and of these, 23 patients had ADC value < 1.25. This association was statistically significant (p < 0.05). The findings of DW MRI were accurate in 72.7% of patients with sensitivity of 63.1%, specificity of 80% and positive predictive value of 70.5%.

Conclusions

Lymph node with ADC value < 1.25 × 10–3 mm2/s has higher probabilities of harbouring malignant cell, so ADC value of DWMRI can be used as a sensitive and specific parameter to differentiate malignant lymph node from benign lymph node. However, our futuristic observation needs to be validated by multi-institutional large sample cohort.

Etiologic heterogeneity of clear-cell and papillary renal cell carcinoma in the Netherlands Cohort Study

At present, mostly case‐control and retrospective studies have investigated the association between etiologic risk factors and the development of histologic subtypes of renal cell carcinoma (RCC). Therefore, we assessed the heterogeneity between body mass index (BMI), cigarette smoking, alcohol consumption and hypertension across clear‐cell RCC (ccRCC) and papillary RCC (pRCC) risk in the prospective Netherlands Cohort Study on diet and cancer. In 1986, 120 852 participants aged 55 to 69 completed a self‐administered questionnaire on diet and other risk factors for cancer. Participants were followed up for cancer through record linkage. Tumor histology was assessed through centralized revision by two experienced uropathologists. After 20.3 years of follow‐up, 384 histologically verified RCC cases, including 315 ccRCC and 46 pRCC cases and 4144 subcohort members were eligible for case‐cohort analysis. Hazard ratios and 95% confidence intervals were estimated by multivariable‐adjusted proportional hazards models. Overall, BMI was associated positively with ccRCC risk, but inversely with pRCC risk. Cigarette smoking was associated with an increased ccRCC, but a decreased pRCC risk. Alcohol consumption was inversely associated with both ccRCC and pRCC risk. Hypertension was associated with an increased risk of both ccRCC and pRCC. Statistically significant etiologic heterogeneity was observed for BMI, BMI change since age 20, and smoking duration in current smokers across ccRCC and pRCC risk. In conclusion, we observed potential heterogeneity for BMI, BMI change and smoking duration across ccRCC and pRCC risk.

What's new?

Etiologic risk factors for clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) include alcohol consumption, body mass index (BMI), cigarette smoking, and hypertension. Little is known, however, about variability in how these factors affect the development of RCC histologic subtypes. In this population‐based prospective cohort study, examination of variability in associations between established etiologic factors and RCC histologic subtypes revealed significant heterogeneity between BMI and ccRCC and pRCC risk and between risk of these subtypes and smoking duration in current smokers. The findings provide novel insight into relationships between etiologic heterogeneity and mechanisms of RCC development.

Pan-Renal Cell Carcinoma classification and survival prediction from histopathology images using deep learning

Histopathological images contain morphological markers of disease progression that have diagnostic and predictive values. In this study, we demonstrate how deep learning framework can be used for an automatic classification of Renal Cell Carcinoma (RCC) subtypes, and for identification of features that predict survival outcome from digital histopathological images. Convolutional neural networks (CNN's) trained on whole-slide images distinguish clear cell and chromophobe RCC from normal tissue with a classification accuracy of 93.39% and 87.34%, respectively. Further, a CNN trained to distinguish clear cell, chromophobe and papillary RCC achieves a classification accuracy of 94.07%. Here, we introduced a novel support vector machine-based method that helped to break the multi-class classification task into multiple binary classification tasks which not only improved the performance of the model but also helped to deal with data imbalance. Finally, we extracted the morphological features from high probability tumor regions identified by the CNN to predict patient survival outcome of most common clear cell RCC. The generated risk index based on both tumor shape and nuclei features are significantly associated with patient survival outcome. These results highlight that deep learning can play a role in both cancer diagnosis and prognosis.

Sonographic Evaluation of Inferior Vena Cava Tumor Thrombus in Renal Cell Carcinoma: A Case Study of a Rare Condition

Inferior vena cava (IVC) tumor thrombus in renal cell carcinoma is a rare entity that suggests heightened biologic behavior and a surgical challenge during the course of treatment. Tumor thrombus can extend from the renal vein to the right atrium. This cephalad extension is classified by four different levels. These levels determine which surgical approach is used, whether a thoracoabdominal incision is needed, and whether a patient needs to be placed in circulatory arrest. Complete surgical resection of the tumor is potentially the only curative treatment, although it supposes a challenge because of operative difficulty and the potential for massive bleeding or tumor pulmonary thromboembolism. IVC tumor thrombus presents with a few differentials that need to be assessed, including bland thrombus, primary IVC leiomyosarcoma, hepatocellular carcinoma, adrenal cortical carcinoma, primary lung carcinoma, and Wilms tumor. The importance of diagnosing IVC tumor thrombus secondary to renal cell carcinoma is demonstrated as well as a sonographic protocol for assessing IVC tumor thrombus.

Cervical lymph node metastasis in chromophobe renal cell carcinoma: a case report and review of the literature

The metastasis of chromophobe renal cell carcinoma to head and neck region, described herein, has never been reported before to our knowledge. A 56-year-old woman with a history of nephrectomy, that revealed chromophobe renal cell carcinoma six years before, presented left cervical mass. Imaging showed with left cervical lymphadenopathies and thyroid nodule. Surgery with histopathological examination confirmed that it was a left central and lateral jugular lymph node metastasis of chromophobe renal cell carcinoma treated postoperatively by antiangiogenic therapy. The patient was successfully treated by surgery and antiangiogenic drugs with stabilization and no recurrence of the metastatic disease. The case and the literature reported here support that chromophobe renal cell carcinoma can metastasize to the head and neck region and should preferentially be treated with surgery and antiangiogenic therapy because of the associated morbidity and quality-of-life issues.

Diabetes and risk of renal cell carcinoma

Background and objectives: There is evidence that the incidence of solid tumors is markedly increased in patients with diabetes mellitus. In the current study, we investigate the association between diabetes and renal cancer.

Patients and Methods: A single-center retrospective analysis of 473 patients who underwent nephrectomy for renal cell carcinoma (RCC) was performed. Diabetic RCC patients were screened for age, gender, ethnicity, HgA1C, glucose levels and renal function.

Results: Of the 473 cases with RCC, we identified 120 patients (25.4%) with a history of diabetes. The incidence of diabetes in RCC patients was higher in female than male subjects and in Hispanic compared to White and Other ethnic backgrounds. At diagnosis, the majority of diabetic RCC patients were 50-59 years of age. In diabetic RCC cases, clear cell type histology (92.0%), nuclear grade 2 (56.1%) and tumor size range from 1-5 cm (65.7%) were the most common in each category.

Conclusion: Our findings indicate that diabetic RCC patients have a predominance of localized, small clear cell RCC. In addition, females with a history of RCC have a higher frequency of diabetes compared to males. This is the first report of clinical and histopathological features of RCC associated with diabetes.

The relationship between human leukocyte antigens (HLA) and renal cell carcinoma

Etiologies of Renal Cell Carcinoma (RCC) are not clear despite of the fact that many risk factors have been suggested. Especially in high stages RCC can affect the immune system in various ways. Human Leukocyte Antigens (HLA) may play a complementary role in the activation between the tumor and immunity. Our aim was to determine the existence of the relationship between HLA system and RCC. By using the standard microlymphocytotoxic method of Terasaki in our study, the HLA A, B, DR and DQ antigen types of 20 patients with RCC Stage T1 and T2 were compared with the control group consisting of healthy 30 people. In our RCC patient group, HLA-A23(9) and DQ7(3) antigens were significantly higher than the control group statistically (p=0.005, p=0.0028; respectively). HLA-A10, DQ1, DR10 and B44 antigens were significantly higher in the control group than the patient group (p=0.011; for all).The findings made us suggest that the people, carrying the antigens which were detected in the patient group, were at high risk for RCC and the people, carrying the protective antigens that were detected in the control group were at less risk for RCC. There may be a dramatic regression for the patients who underwent immunotherapy and HLA expression, which is known to play role in tumor biology, may direct the effects of immunotherapeutic agents. Immunologic description and destruction is avoided in case of change or disappearance of HLA expression by cancer cells. Further investigations which will be performed in our population in the future will be more illuminating to confirm those results. We have concluded that, HLA profiles may be evaluated for detection the people at risk of RCC, the prognosis of the patients and their treatments.

Nicotinamide N-methyltransferase induces cellular invasion through activating matrix metalloproteinase-2 expression in clear cell renal cell carcinoma cells

Nicotinamide N-methyltransferase (NNMT) was recently identified as one clear cell renal cell carcinoma (ccRCC)-associated gene by analyzing full-length complementary DNA-enriched libraries of ccRCC tissues. The aim of this study is to investigate the potential role of NNMT in cellular invasion. A strong NNMT expression is accompanied with a high invasive activity in ccRCC cell lines, and small interfering RNA-mediated NNMT knockdown effectively suppressed the invasive capacity of ccRCC cells, whereas NNMT overexpression markedly enhanced that of human embryonic kidney 293 (HEK293) cells. A positive correlation between the expression of NNMT and matrix metallopeptidase (MMP)-2 was found in ccRCC cell lines and clinical tissues. The treatment of blocking antibody or inhibitor specific to MMP-2 significantly suppressed NNMT-dependent cellular invasion in HEK293 cells. Furthermore, SP-1-binding region of MMP-2 promoter was found to be essential in NNMT-induced MMP-2 expression. The specific inhibitors of PI3K/Akt signaling markedly decreased the binding of SP1 to MMP-2 promoter as shown by chromatin immunoprecipitation assay. We also demonstrated that PI3K/Akt pathway plays a role in NNMT-dependent cellular invasion and MMP-2 activation. Moreover, short hairpin RNA-mediated knockdown of NNMT expression efficiently inhibited the growth and metastasis of ccRCC cells in non-obese diabetic severe combined immunodeficiency mice. Taken together, the present study suggests that NNMT has a crucial role in cellular invasion via activating PI3K/Akt/SP1/MMP-2 pathway in ccRCC.

Magnetic resonance imaging of renal masses

The increasing frequency of incidentally detected renal masses supports the need for accurate imaging characterization to avoid unnecessary surgery/interventional procedures. Furthermore, the need for accurate presurgical diagnosis of specific histologic subtypes of renal malignancies is increasingly important as advances in understanding of tumor biology direct targeted courses of therapy. Magnetic resonance imaging is uniquely suited for the evaluation of renal masses because of its ability to provide excellent soft-tissue contrast and demonstration of enhancement, as well as its multiplanar capabilities. Although the spectrum of masses that may occur in the kidneys is broad, specific imaging features may assist in their accurate diagnosis. Examples of the imaging appearance of common and uncommon renal masses are provided along with a protocol for comprehensive magnetic resonance examination of the kidneys.

Renal cell carcinoma: dynamic contrast-enhanced MR imaging for differentiation of tumor subtypes--correlation with pathologic findings

PURPOSE

To retrospectively evaluate whether the enhancement patterns of pathologically proved clear cell, papillary, and chromophobe renal cell carcinomas (RCCs) measured on clinical dynamic contrast agent-enhanced magnetic resonance (MR) images permit accurate diagnosis of RCC subtype.

MATERIALS AND METHODS

This study was Institutional Review Board approved and HIPAA compliant; informed consent was waived. One hundred twelve patients (76 men, 36 women; age range, 25-88 years; mean age, 58.1 years) underwent MR imaging of 113 renal masses (mean diameter, 5.4 cm) with pathologic diagnoses of clear cell (n = 75), papillary (n = 28), or chromophobe (n = 10) RCC. A 1.5-T clinical MR protocol was used before and after (corticomedullary and nephrographic phases) intravenous administration of contrast agent. Region-of-interest measurements within tumor and uninvolved renal cortex were used to calculate percentage signal intensity change and tumor-to-cortex enhancement index. Subtype groups were compared by using linear mixed-effects models. Receiver operating characteristic (ROC) curve analysis was performed for the comparison of clear cell and papillary RCCs.

RESULTS

On both the corticomedullary and nephrographic phase images, clear cell RCCs showed greater signal intensity change (205.6% and 247.1%, respectively) than did papillary RCCs (32.1% and 96.6%, respectively) (P < .001). Chromophobe RCCs showed intermediate change (109.9% and 192.5%, respectively). The tumor-to-cortex enhancement indexes at corticomedullary and nephrographic phases were largest for clear cell RCCs (1.4 and 1.2, respectively), smallest for papillary RCCs (0.2 and 0.4, respectively), and intermediate for chromophobe RCCs (0.6 and 0.8, respectively). Signal intensity changes on corticomedullary phase images were the most effective parameter for distinguishing clear cell and papillary RCC (area under ROC curve, 0.99); a threshold value of 84% permitted distinction with 93% sensitivity and 96% specificity.

CONCLUSION

Clear cell, papillary, and chromophobe RCCs demonstrate different patterns of enhancement on two-time point clinical dynamic contrast-enhanced MR images, allowing their differentiation with high sensitivity and specificity.

Renal cell carcinoma: diagnosis, staging, and surveillance

OBJECTIVE

This educational review focuses on the staging and radiologic evaluation of renal cell carcinoma. It includes discussion of the epidemiology, pathology, and therapeutic options of renal cell carcinoma and the implications for radiologic follow-up.

CONCLUSION

The incidence of renal cell carcinoma has been increasing. Imaging plays a central role in its detection, staging, and treatment evaluation and follow-up.

Application of Immunohistochemistry to the Genitourinary System (Prostate, Urinary Bladder, Testis, and Kidney)

Context.—The variety of morphologic patterns of different entities of the genitourinary tract can present a diagnostic dilemma for the pathologist. This is especially true in cases of mimics of cancer, a cancer of unknown primary, or poorly differentiated tumors, in which it is hard to assign histogenesis needed to plan the correct therapy for the patient. Immunohistochemistry offers a better capacity than hematoxylin-eosin staining alone to differentiate human tissue types. Also, in the past decades, several techniques had been developed to differentiate between benign and malignant processes with morphologic overlap. By using immunohistochemistry in selected cases, the rate of false-negative and false-positive diagnoses can be reduced, and some patients are afforded the opportunity to get more specific or effective therapy as a result.

Objective.—For each subgroup of genitourinary system tumors, common diagnostic problems are reviewed, and immunohistochemical markers useful in addressing these problems are discussed, along with expected patterns of immunoreactivity.

Data Sources.—The pertinent literature, with focus on immunohistochemical staining of tumors of the genitourinary tract.

Conclusions.—The addition of immunohistochemistry to the diagnostic armamentarium for genitourinary pathologic diagnosis has increased the sensitivity and specificity of diagnoses and aided in the selection of optional therapeutic regimens in selected cases.

[Solid renal mass up to 4 cm. Analysis of the diagnostic procedures, TNM staging and surgical treatment]

OBJECTIVES

We perform a retrospective review of renal tumors operated with a maximum size of 4 cm to determine if the diagnostic methodology was adequate, the TMN staging prognostic accuracy (UICC 2002) and the goal surgical treatment.

MATERIAL AND METHOD

Between 1984 to 2005, 78 renal units form 74 patients (4 bilateral synchronous) operated at the Service of Urology of the Hospital Alemán de Buenos Aires. Age distribution, sex, presentation form (incidental and symptomatic), diagnostic methodology, laboratory variables, surgical treatment (partial or radical surgery), histopathology, Fuhrman grade, tumor size, bilaterality, multicentricity, TNM staging, evolution and survival (Kaplan Meier) were analyzed.

RESULTS

78 renal units from a total of 192, 40.62% were analyzed. The median age was 58.72 years. 69% were male and 31% female. The presentation form was 91.90 % incidental and symptomatic 8.10% (Hematuria in 5 and lung metastasis in 1). The diagnosis was performing with ultrasound and CT scan 63 cases, in 4 was also used resonance magnetic imaging (RMI) and in 7 ultrasound and RMI. Arteriography was used in 11 cases, 3 showed tumor and 8 were normal. Biopsy was performing in 5 cases, all positive for clear cells carcinoma. Globular sedimentation was the only one laboratory abnormality in 12 cases. Surgical treatment was radical surgery in 35 renal units (44.87%) and conservative surgery in 43 units (55.13%). Pathology clear cells carcinoma (CCC) 79.48%, papillary carcinoma 1.28%, angiomyolipoma (AML) 8.97%, oncocytoma 7.69% and adenoma 2.56%. The Fuhrman grade was 1 in 76.19%; 2 in 20.63% and 3 in 3.18%. Bilateral tumor were found in 4 cases 2 CCC, 1 CCC and AML and 1 CCC and adenoma. Tumor median size was 2.93 cm. Staging was T1a 96.82%, T3a 1.59% and T3aM+ 1.59%. Follow-up could be made in 54 of 61 cases. At median follow-up of 52.25 months, 50 cases were disease free, 3 died by progression at 18, 33 and 82 months and all of them were symptomatic tumors, 1 died by a non related cause. Survival rate was 94%.

CONCLUSIONS

1)Ultrasound and CT scan obtained a highest diagnostic accuracy for solid renal mass. Biopsy in selective cases could contribute to achieve a correct treatment strategy. 2) Conservative surgery was the goal treatment in selected tumors up to 4 cm. and we believe that TNM staging should contemplate the presentation form to improve the prognostic value.

Contrast-enhanced ultrasonography in the diagnosis of solid renal tumors

OBJECTIVE

The purpose of this study was to evaluate the usefulness of contrast-enhanced ultrasonography (CEUS) in the diagnosis of solid renal tumors.

METHODS

Twenty-nine patients with solid tumors detected on gray scale ultrasonography underwent resection for suspected renal malignancy. Findings of arterial phase contrast computed tomography (CT) and CEUS were compared for each diagnosis.

RESULTS

Histopathologic examination of resected lesions showed malignancy in 26 patients (clear cell carcinoma, n = 18; papillary renal cell carcinoma, n = 6; collecting duct carcinoma, n = 1; and infiltrative urothelial carcinoma, n = 1) and benign tumors in 3 patients (oncocytoma, n = 2; and angiomyolipoma, n = 1). Contrast CT failed to show tumor blood flow in 5 of 29 patients, whereas CEUS showed this in all patients. Positive predictive values of CEUS and contrast CT in the diagnosis of renal malignancy were 100% and 82.8%, respectively. Among clear cell carcinomas, hypervascularity was observed on contrast CT in 16 of 18 patients and on CEUS in 17 of 18 patients. On the basis of hypervascularity, diagnostic sensitivity values for clear cell carcinoma were 94.4% for CEUS and 88.9% for contrast CT, whereas specificity values were 45.5% for CEUS and 72.7% for contrast CT. Among papillary cell carcinomas, contrast CT showed avascular lesions in 4 of 6 patients. However, CEUS showed blood flow in these lesions, leading to diagnosis of hypovascular renal tumors.

CONCLUSIONS

Contrast-enhanced ultrasonography was more sensitive for detecting slight tumor blood flow than contrast CT and was useful in preoperatively diagnosing malignant hypovascular renal tumors but was less so for hypervascular renal tumors.

Differentiation of renal cell carcinoma subtypes by multislice computerized tomography

PURPOSE

We differentiated renal cell carcinoma subtypes using multislice computerized tomography (CT).

MATERIALS AND METHODS

We reviewed the CT images of 87 patients with renal cell carcinoma. Three subtypes of renal cell carcinoma were noted, including clear cell in 37 cases, papillary in 26 and chromophobe in 24. Biphasic CT (unenhanced, corticomedullary and excretory phases) was done in all patients. We compared patient age and sex, tumor size, enhancement degree and pattern (homogeneous, heterogeneous and predominantly peripheral), the presence or absence of calcification or cystic degeneration (necrotic or hemorrhagic areas within the tumor) and tumor spreading patterns, including perinephric change, venous invasion and lymphadenopathy, in the 3 subtypes.

RESULTS

The degree of enhancement was significantly different among the 3 subtypes in the corticomedullary and excretory phases (p <0.001). Cystic degeneration was more evident in the clear cell subtype than in the other subtypes regardless of tumor size (p <0.001). A hypervascular pattern (higher tumor enhancement after contrast material injection due to higher vascularity) was noted in 48.6% of clear cell subtype in comparison to 15.4% of papillary and 4.2% of chromophobe subtypes (p <0.001). The chromophobe subtype showed homogeneous enhancement in 75% of cases in comparison to 45% and 65% of clear cell and papillary subtypes (p >0.05). Calcification was evident in 21.6%, 23.1% and 25% of clear cell, papillary and chromophobe subtypes, respectively (p >0.05).

CONCLUSIONS

To differentiate the subtypes of renal cell carcinoma the degree of enhancement is the most valuable parameter. The presence or absence of cystic degeneration, vascularity and enhancement patterns can serve supplemental role in differentiating renal cell carcinoma subtypes.

A Review of Prognostic Pathologic Features and Algorithms for Patients Treated Surgically for Renal Cell Carcinoma

Accurate subtyping of RCC is critically important and should be considered in algorithms that are developed as prognostic tools for the patient and clinician. The TNM classification, already a powerful prognostic factor, will continue to evolve. The authors recommend that each component of the classification be assessed and reported during pathologic examination. This article also highlighted the importance of assigning a nuclear grade that is based on standardized and reproducible criteria that reflect the heterogeneity of nuclear and nucleolar features within RCC. Lastly, it is increasingly evident that coagulative tumor necrosis and sarcomatoid differentiation are compelling prognostic factors, on par with nuclear grade, and should be assessed routinely. To conclude, the complete list of pathologic features that are evaluated as part of the Mayo Clinic Nephrectomy Registry is presented. The features that are reported routinely in clinical practice also are indicated; this can serve as a guide for the reporting of results from the pathologic examination of RCC.

Renal cell carcinoma in South Korea: a multicenter study

The incidence of renal cell carcinoma (RCC) in South Korea is steadily becoming similar to that in Western countries. This study summarizes the results of a 3-year multicenter survey of RCC in South Korea, conducted by the Korean Genitourinary Pathology Study Group. A total of 795 cases of RCC were collected from 20 institutes between 1995 and 1997, including 686 clear cell RCCs (86.3%), 58 papillary RCCS (7.30%), 49 chromphobe RCCs (6.16%), and 2 collecting duct RCCs (0.25%). At least 5 years of follow-up was available for 627 clear cell, 54 papillary, and 49 chromophobe RCCs. All subtypes presented most frequently with stage T3aN0M0 at the time of operation, and papillary RCCs demonstrated more frequent lymph node metastasis. Overall survival was not significantly related to the histological subtype (clear cell vs papillary, P = 0.8651; clear cell vs chromophobe, P = 0.0584; papillary vs chromophobe, P = 0.0743). For clear cell RCCs, statistically significant associations were found between overall survival and sex (P = 0.0153), multiplicity (P = 0.0461), necrosis (P = 0.0191), age, sarcomatoid change, TNM stage, nuclear grade, and modality of treatment (all P <0.0001). Overall survival was significantly associated with tumor size (P = 0.0307), nuclear grade (P = 0.0235), multiplicity, sarcomatoid change, and TNM stage (all P <0.0001) for papillary RCCs and with the presence of sarcomatoid change (P = 0.0281), nuclear grade (P = 0.0015), treatment modality (P = 0.0328), and TNM stage (P <0.0001) for chromophobe RCCs. Age (P = 0.0125), nodal stage (P = 0.0010), and treatment modality (P = 0.0001) were significant independent prognostic indicators for clear cell RCC on multivariate analysis. This is the first multicenter study of RCC in South Korea, demonstrating the general patterns and prognostic factors of Korean RCCs.

Renal cell carcinoma: analysis of postoperative recurrence patterns

PURPOSE

To retrospectively analyze the recurrence patterns of renal cell carcinoma (RCC) and the factors affecting tumor recurrence.

MATERIALS AND METHODS

The institutional review board approved this study; patient informed consent was not required. There were 162 men (mean age, 54 years +/- 13 [standard deviation]) and 32 women (mean age, 56 years +/- 11) who had undergone complete surgical resection of RCC. Mean follow-up period was 45 months (range, 7-92 months). In consensus, two radiologists determined the presence or absence of tumor recurrence and recorded the time and sites of tumor recurrence. The relationships between tumor recurrence and tumor factors, including greatest diameter (> or =5 cm or <5 cm), T stage, N stage, stage group, histologic subtype, and nuclear grade, were evaluated by using Kaplan-Meier statistics.

RESULTS

Tumor recurred in 41 (21%) patients. The mean time of tumor recurrence was 17 months (range, 3-50 months). Tumor recurred within 2 years after surgery in 34 (83%) patients. Tumor recurrence sites included lung (n = 29), bone (n = 13), the nephrectomy site (n = 7), brain (n = 6), liver (n = 5), mediastinal lymph nodes (n = 5), the contralateral kidney (n = 4), and the neck muscles (n = 2). The recurrence rate was greater for tumors 5 cm or larger than for those smaller than 5 cm, greater for T3a or T3b tumors than for T1 tumors, greater for stage III tumors than for stage I tumors, and greater for tumors with a nuclear grade of 3 or 4 than for those with a nuclear grade of 1 or 2 (P < .05 for all).

CONCLUSION

RCC usually recurs within 2 years after surgery, with the lung being the most vulnerable site; greatest tumor diameter, T stage, stage group, and nuclear grade are important factors for recurrence.

Endobronchial metastasis from renal cell carcinoma: CT findings in four patients

PURPOSE

To describe the CT findings of an endobronchial metastasis from a renal cell carcinoma (RCC).

MATERIALS AND METHODS

The CT findings and clinical features of a histologically proven endobronchial metastasis from a RCC in four patients (three male, one female; age range, 64-80 years; mean age, 69 years) were reviewed retrospectively. The location of the metastasis in the airway, shape, the degree of tumor enhancement, and the associated pulmonary parenchymal abnormalities were analyzed.

RESULTS

The histological subtype of the endobronchial metastases from the RCC was conventional in all cases. The tumors were located at the lobar (n = 1), both the lobar and segmental (n = 2), or the segmental (n = 1) bronchus. On the CT scan, the tumors were polypoid (n = 1), had a glove-finger appearance (n = 2), and exhibited branching in the airways and bronchial wall thickening (n = 1). The endobronchial metastasis from the RCC showed very high attenuation (84-128 HU), and strong enhancement (51.6-93.3 HU) on the contrast-enhanced CT images. The lung parenchymal lesions that had reticular opacities and ground glass opacities (n = 3).

CONCLUSIONS

An endobronchial metastasis from a RCC appears as a strong-enhancing mass or bronchial wall thickening, accompanied by reticular opacities and ground glass opacities.

Imaging of hereditary renal cancer

Over the past 5 years there have been dramatic developments in the extent of knowledge of hereditary renal cancers. In addition to VHL, which is associated with clear cell carcinoma, one can now list HPRC (associated with type I papillary renal cancer) and HLRCC (associated with type II papillary renal cancer). BHD and FRO are associated with chromophobe carcinoma and oncocytomas, although other histologic tumor types have been found in BHD. Medullary carcinoma of the kidney is associated with sickle cell trait. Although the genes associated with these tumors have been discovered, the exact mechanisms by which they cause renal cancer remain to be elucidated. It is quite likely that other genes also are involved in this process. Using VHL as an example, research is now underway on targeting mutant pVHL or excess HIF for diagnostic and therapeutic purposes. Understanding the mechanisms leading to cancer may open new targets of opportunity for drug development. This improved knowledge of the biogenetic pathways used to form tumors will impact the development of new therapeutic techniques for treating renal cancers in hereditary and nonhereditary forms of the disease.

Comparisons of outcome and prognostic features among histologic subtypes of renal cell carcinoma

Our objective was to compare cancer-specific survival and to examine associations with outcome among the histologic subtypes of renal cell carcinoma (RCC). We studied 2385 patients whose first surgery between 1970 and 2000 was a radical nephrectomy for sporadic, unilateral RCC. All RCC tumors were classified following the 1997 Union Internationale Contre le Cancer and American Joint Committee on Cancer guidelines. There were 1985 (83.2%) patients with clear cell, 270 (11.3%) with papillary, 102 (4.3%) with chromophobe, 6 (0.3%) with collecting duct, 5 (0.3%) with purely sarcomatoid RCC and no underlying histologic subtype, and 17 (0.7%) with RCC, not otherwise specified. Cancer-specific survival rates at 5 years for patients with clear cell, papillary, and chromophobe RCC were 68.9%, 87.4%, and 86.7%, respectively. Patients with clear cell RCC had a poorer prognosis compared with patients with papillary and chromophobe RCC (p <0.001). This difference in outcome was observed even after stratifying by 1997 tumor stage and nuclear grade. There was no significant difference in cancer-specific survival between patients with papillary and chromophobe RCC (p = 0.918). The 1997 TNM stage, tumor size, presence of a sarcomatoid component, and nuclear grade were significantly associated with death from clear cell, papillary, and chromophobe RCC. Histologic tumor necrosis was significantly associated with death from clear cell and chromophobe RCC, but not with death from papillary RCC. Our results demonstrate that there are significant differences in outcome and associations with outcome for the different histologic subtypes of RCC, highlighting the need for accurate subtyping.

Staging Renal Cell Carcinoma With Helical CT: The Revised 1997 AJCC and UICC TNM Criteria

The TNM staging system for renal cell carcinoma, revised in 1997 by the UICC and AJCC, has important implications for tumor prognosis and surgical planning. Multislice helical CT of the kidneys plays a vital role in the detection, characterization, and staging of renal cell carcinoma, and for surgical planning. Radiologists should be familiar with state-of-the-art helical CT techniques, the revised TNM staging criteria, and the varied appearances of renal tumors, tumor cell types, and the wide variety of metastatic disease that occurs in advanced cases.

Differentiation of subtypes of renal cell carcinoma on helical CT scans

OBJECTIVE

The purpose of our study was to differentiate subtypes of renal cell carcinoma on helical CT scans.

MATERIALS AND METHODS

We reviewed CT scans of four subtypes of renal cell carcinoma: 76 conventional (clear cell), 19 papillary, 13 chromophobe, and two collecting duct. Biphasic CT scans (unenhanced, corticomedullary, and excretory phase scans) were obtained in 61 patients, and monophasic CT scans (unenhanced and excretory phase scans) in 49. We compared patient age and sex; tumor size; degree and pattern (homogeneous, heterogeneous, predominantly peripheral) of enhancement; presence or absence of calcification; and tumor-spreading patterns including perinephric change, venous invasion, and lymphadenopathy in four subtypes.

RESULTS

Conventional renal carcinoma showed stronger enhancement than the other subtypes (p < 0.05): 106 +/- 48 H (mean +/- SD) in the corticomedullary phase and 62 +/- 25 H in the excretory phase. The sensitivity and specificity for differentiating conventional renal carcinoma from the other subtypes were 74% and 100% when 84 H was used as the cutoff value in the corticomedullary phase and 84% and 91% when 44 H was used as the cutoff value in the excretory phase. Conventional (84%), papillary (74%), and collecting duct (100%) renal carcinomas tended to show heterogeneous or predominantly peripheral enhancement, whereas chromophobe renal carcinoma (69%) usually showed homogeneous enhancement. Calcification was more common in papillary (32%) and chromophobe (38%) renal carcinomas than in conventional renal carcinoma (11%) (p < 0.05). Perinephric change and venous invasion were not noted in chromophobe renal carcinoma, whereas both were common in collecting duct renal carcinoma.

CONCLUSION

For the differentiation of the subtypes of renal cell carcinoma, degree of enhancement is the most valuable parameter; enhancement pattern, the presence or absence of calcification, and tumor-spreading patterns can serve supplemental roles in the identification of the subtype of renal cell carcinoma.

Unilateral renal cell carcinoma with coexistent renal disease: a rare cause of end-stage renal disease

BACKGROUND

Renal cell carcinoma (RCC) is a disorder encompassing a wide spectrum of pathological renal lesions. Coexistence of unilateral RCC and associated pathology in the contralateral kidney is an unusual and challenging therapeutic dilemma that can result in renal failure. So far, data on unilateral RCC with chronic renal failure necessitating renal replacement therapy have not been published. The aim of the present study was to evaluate the incidence of end-stage renal disease (ESRD) from unilateral RCC, and to assess the associated pathology and possible pathogenic factors.

METHODS

In 1999, a survey of the 350 patients treated by chronic dialysis in Asturias, Spain, was carried out to identify and collect clinical information on patients with primary unilateral RCC whilst on their renal replacement programme.

RESULTS

Seven patients were identified as having ESRD and unilateral RCC, giving an incidence of 2% of patients treated by dialysis. There was a wide spectrum of associated disease and clinical presentation. All patients underwent radical or partial nephrectomy and were free of recurrence 6--64 months after surgery. Six patients were alive and free of malignancy recurrence for 6--30 months after the onset of haemodialysis.

CONCLUSION

ESRD is rare in association with unilateral RCC, but does contribute to significant morbidity. However, the data presented here are encouraging and suggest that cancer-free survival with renal replacement therapy can be achieved in such patients.