Sarcomatoid renal carcinoma: the final common dedifferentiation pathway of renal epithelial malignancies

Sarcomatoid features, necrosis, and grade are prognostic factors in metastatic clear cell renal cell carcinoma with vascular endothelial growth factor-targeted therapy

Various clinical and laboratory parameters are used to determine the prognosis of patients with renal cell carcinoma (RCC), but the prognostic significance of histologic features has not been fully examined in patients with metastatic clear cell RCC receiving vascular endothelial growth factor (VEGF)/tyrosine kinase inhibitor (TKI; VEGF-TKI)-targeted therapy. To define prognostic clinicopathological factors, 83 such patients were retrospectively analyzed. Of these patients, 38 (45.8%) showed response to VEGF-TKI, whereas 45 (54.2%) were nonresponsive. Response to VEGF-TKI was associated with less than 10% sarcomatoid features and less than 10% tumor necrosis. Multivariate analysis showed that tumor necrosis was independently prognostic of VEGF-TKI response. During a median follow-up of 18 months (range, 1-62 months), 54 patients (65.1%) showed disease progression and 44 (53.0%) died. Shorter progression-free survival and overall survival (OS) were associated with a period less than 1 year from initial diagnosis to VEGF-TKI initiation, high Fuhrman grade, at least 10% sarcomatoid features, and at least 10% tumor necrosis. In addition, thrombocytosis was associated with shorter OS. Multivariate analysis showed that sarcomatoid features was independently prognostic of progression-free survival, whereas time from initial diagnosis to VEGF-TKI initiation and sarcomatoid features were independent prognostic factors of OS. In summary, sarcomatoid features, tumor necrosis, and tumor grade are histologic prognostic factors and should be considered in determining whether to initiate targeted treatment in patients with metastatic clear cell RCC.

Sarcomatoid variant of urothelial carcinoma (carcinosarcoma, spindle cell carcinoma): a review of the literature

Background. Sarcomatoid variant of urothelial carcinoma (SVUC) was added to the WHO classification in 2004. Aims. To review the literature. Materials and Method. Various internet databases were used. Result. SVUCs are rare biphasic malignant neoplasms exhibiting morphologic/immunohistochemical evidence of epithelial and mesenchymal differentiation with the presence or absence of heterologous elements. Some cases of SVUC have been associated with radiation therapy and cyclophosphamide treatment. Patients' ages range from 50 to 77 years (mean age 66). Patients tend to be younger and they more commonly presented with high-grade histology and advanced stage disease, in comparison with patients who had conventional urothelial carcinoma (CUC). Results of molecular/genetic studies strongly argue for a common monoclonal cell origin of both the epithelial and mesenchymal components in SUVC. The cancer specific survival of SVUC is poor in comparison with CUC. Radical surgical excision and chemoradiation may be associated with improved prognosis; chemoradiation as an organ preserving alternative to radical excision may be associated with improved outcome. There is no consensus opinion on the best treatment modalities for SUVC. Conclusions. SVUC is rare and is associated with inferior outcome compared with CUC. A multicentre trial of various treatment options is required. Cases of SVUC should be reported.

Ancillary diagnostic techniques in the evaluation of adult epithelial renal neoplasms: indications, caveats, and pitfalls

The role played currently by the different ancillary diagnostic techniques in the diagnosis of adult epithelial renal tumors continues to be debated. It has also become clear that in some instances light microscopic appearance alone cannot be used to classify these neoplasms into specific categories with the degree of precision required for therapeutic purposes. Renal cell carcinoma (RCC) subtypes may share common histologic characteristics but exhibit different biological behavior and response to therapy which clearly indicates the crucial role that advanced pathologic speciation plays in the current assessment of these neoplasms. Although immunohistochemistry is widely used for the purpose of categorizing renal tumors because of its widespread availability, the immunoprofiles of the various types of renal neoplasms overlap significantly, making definitive diagnostic determinations difficult and challenging at times. This manuscript will address how ancillary diagnostic techniques can be incorporated into the routine evaluation of neoplastic renal masses to improve classification. Both cytology and surgical specimens will be addressed, as fine needle aspiration (FNA) is being used with preference in many cases in the diagnosis of renal masses. Surgical and cytopathologists must intelligently select the ancillary diagnostic technique/s that will provide the information needed to solve the differential diagnosis under consideration in a given case. However, in some cases >1 of these techniques should be used to make an accurate diagnosis with the aim of arriving at an unequivocal diagnosis. The identification of specific signaling pathways that are defective in certain types of renal neoplasms has made possible the design of target-specific therapies that are directed towards the aberrant pathways associated with the defective proteins found in these tumors. This makes the exact classification of these neoplasms and the detection of these aberrant proteins targeted for treatment an absolute requirement for the application of these molecular-based therapeutic interventions. The role that the pathologic assessment plays in the classification of renal tumors becomes more important than ever to take advantage of this and similar new molecular-oriented therapies.

Prognostic effect of sarcomatoid dedifferentiation in patients with surgically treated renal cell carcinoma: a matched-pair analysis

BACKGROUND

The aim of this study was to assess the prognostic relevance of SD in patients with RCC.

PATIENTS AND METHODS

Among 8126 RCC patients surgically treated at 12 academic centers (members of the Collaborative Research on Renal Neoplasms Association [CORONA] project), 316 patients (3.9%) had SD with sarcomatoid areas comprising at least 10% of the tumor tissue. After propensity score-based matched-pair analysis, 281 with and 281 matched RCC patients without SD remained available for direct comparison of cancer-specific survival (CSS). Median follow-up was 36.5 months (interquartile range, 15-82). Uni- and multivariable Cox proportional hazards regression analyses were performed to assess the prognostic value of parameters.

RESULTS

In univariable analysis, there was no difference in CSS between patients with or without SD (1 and 5 years CSS, 79% vs. 83% and 59% vs. 64%, respectively; hazard ratio, 1.21; P = .16). Multivariable analysis in patients with SD identified metastatic dissemination at the time of surgery, pT-stage, nodal status, and tumor size as independent predictors of CSS. This study was limited by its retrospective multicenter design and lack of central histopathological review.

CONCLUSION

Sarcomatoid dedifferentiation was not an independent predictor of CSS in surgically treated RCC patients in the present matched-pair series. Because pathology reports form the basis on which study specimens are selected for further studies, which are clearly needed to advance our understanding of the prognostic value of SD in RCC, it is imperative that pathologists reliably report on absence or presence and the estimated percentage of a coexisting sarcomatoid component.

Differential expression of prognostic proteomic markers in primary tumour, venous tumour thrombus and metastatic renal cell cancer tissue and correlation with patient outcome

Renal cell carcinoma (RCC) is the most deadly of urological malignancies. Metastatic disease affects one third of patients at diagnosis with a further third developing metastatic disease after extirpative surgery. Heterogeneity in the clinical course ensures predicting metastasis is notoriously difficult, despite the routine use of prognostic clinico-pathological parameters in risk stratification. With greater understanding of pathways involved in disease pathogenesis, a number of biomarkers have been shown to have prognostic significance, including Ki67, p53, vascular endothelial growth factor receptor 1 (VEGFR1) and ligand D (VEGFD), SNAIL and SLUG. Previous pathway analysis has been from study of the primary tumour, with little attention to the metastatic tumours which are the focus of targeted molecular therapies. As such, in this study a tissue microarray from 177 patients with primary renal tumour, renal vein tumour thrombus and/or RCC metastasis has been created and used with Automated Quantitative Analysis (AQUA) of immunofluorescence to study the prognostic significance of these markers in locally advanced and metastatic disease. Furthermore, this has allowed assessment of differential protein expression between the primary tumours, renal vein tumour thrombi and metastases. The results demonstrate that clinico-pathological parameters remain the most significant predictors of cancer specific survival; however, high VEGFR1 or VEGFD can predict poor cancer specific survival on univariate analysis for locally advanced and metastatic disease. There was significantly greater expression of Ki67, p53, VEGFR1, SLUG and SNAIL in the metastases compared with the primary tumours and renal vein tumour thrombi. With the exception of p53, these differences in protein expression have not been shown previously in RCC. This confirms the importance of proliferation, angiogenesis and epithelial to mesenchymal transition in the pathogenesis and metastasis of RCC. Importantly, this work highlights the need for further pathway analysis of metastatic tumours for overcoming drug resistance and developing new therapies.

c-KIT: potential predictive factor for the efficacy of sorafenib in metastatic renal cell carcinoma with sarcomatoid feature

BACKGROUND

Vascular endothelial growth factor-targeted therapy has been standard care for metastatic renal cell carcinoma for years. However, little clinical experience on these agents in the treatment of sarcomatoid tumors has been documented. The aim of the present study was to detect the expression of c-KIT in the primary tumor of metastatic renal cell carcinoma with sarcomatoid feature, and to reveal its potential value of predicting the efficacy of sorafenib treatment and survival of the patients.

PATIENTS AND METHODS

Seventeen patients were enrolled and treated with sorafenib as a second-line treatment after cytokine therapy. The expressions of c-KIT was tested immunohistochemically in the 17 specimens of primary renal tumors. The correlation between c-KIT status and treatment effect was compared. Univariate and multivariate analysis were employed to determine the survival difference between c-KIT-positive and c-KIT-negative patients.

RESULTS

Twelve of 17 specimens (70.6%) were detected to be overexpressing c-KIT. c-KIT positive patients had higher disease control rate (75%) compared with c-KIT-negative patients (25%), P = .036. Median overall survival time was 92 weeks for c-KIT positive patients and 44 weeks for c-KIT negative patients, log rank χ(2) = 9.566, P = .002. Multivariate Cox regression model analysis only revealed number of metastatic organs and c-KIT as independent prognostic factors.

CONCLUSION

Our findings suggest that c-KIT can be a potential predictive factor for metastatic renal cell carcinoma with sarcomatoid feature in treatment using sorafenib, and patients with positive c-KIT expression might have better responses and obtain longer overall survival time.

A novel case of concurrent renal tumors: chromophobe renal cell carcinoma and carcinoid tumor of the kidney with brief review of renal neuroendocrine tumors

Renal cell carcinoma of chromophobe type is a malignant neoplasm with characteristic large cells that exhibit prominent cell membranes. Primary renal carcinoid tumors are rare tumors with the histological appearance similar to well-differentiated neuroendocrine tumors at other sites. Chromophobe renal cell carcinoma with neuroendocrine differentiation is exceedingly rare. The authors describe a case of a chromophobe renal cell carcinoma and carcinoid tumor of the kidney presenting as distinct masses in the same kidney in a 34-year-old male. The histologic and immunohistochemical features of both the tumors were characteristic with no overlapping features. The carcinoid tumor presented at a higher stage with nodal metastasis. To the best of the authors' knowledge, this is the first case of 2 morphologically distinct tumors, one chromophobe renal cell carcinoma and the other primary carcinoid tumor in the same kidney.

Cancer stem cells in tumor heterogeneity

Cancer cells within a given tumor were long regarded as a largely homogeneous group of cells originating from a common progenitor cell. However, it is increasingly appreciated that there is a considerable heterogeneity within tumors also on the tumor cell level. This heterogeneity extends to virtually all measurable properties of cancer cells, ranging from differentiation state, proliferation rate, migratory and invasive capacity to size, and therapeutic response. Such heterogeneity likely represents a major therapeutic hurdle, but the mechanisms underlying its emergence remain poorly understood and a controversial topic. The cancer stem cell model of tumor progression has gained increasing support during the past several years. In this review, I will discuss some major implications of the cancer stem cell hypothesis on the origins of tumor heterogeneity, focusing both on heterogeneity within the tumor cells proper and on potential transdifferentiation of cancer stem cells into stromal and endothelial lineages, as well as on heterogeneity of the therapeutic response. Evidence for and against a direct and causal role of cancer stem cells in the emergence of tumor heterogeneity will be weighed and alternative explanations for apparently contradictory observations discussed. Finally, I will discuss the potential origins of cancer stem cells and the various implications of origin to the contribution to tumor heterogeneity, and outline some future directions.

Impact of pathological tumour characteristics in patients with sarcomatoid renal cell carcinoma

Study Type - Prognosis (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Sarcomatoid renal cell carcinoma can occur in the setting of all histological subtypes of kidney cancer. These tumours are very aggressive and many patients present with disseminated disease. Long-term survival is poor and the durable responses to systemic therapy are infrequent. Our large cohort analyses the influence of pathological tumour characteristics in determining prognosis for patients with sarcomatoid renal cell carcinoma undergoing surgical resection. This series helps define the prognostic influence of histological subtype, type of sarcomatoid morphology, the percentage necrosis and sarcomatoid features, and the presence of microvascular invasion.

OBJECTIVES

To examine the influence of pathological tumour characteristics on survival to aid prognostication and clinical trial design. Patients with sarcomatoid renal cell carcinoma (sRCC) are known to have poor prognosis and response to systemic therapy.

PATIENTS AND METHODS

A single-centre database was reviewed to identify all patients with sRCC. Clinical variables and pathological information, including histology, necrosis, percentage of sarcomatoid features (PSF) and microvascular invasion (MVI), were recorded and correlated to outcome.

RESULTS

Analyses of 104 patients with sRCC found that the median (range) size of tumours was 9.5 cm (2.5-30), 65% of patients had areas of clear cell histology, and 69.2% had metastatic disease at presentation. The PSF did not influence tumour size, stage, necrosis, MVI, nodes or metastasis. A total of 85 patients (81.7%) died during the follow-up period with a median (95% confidence interval [CI]) survival of 5.9 months (4.7-8.9). In the overall cohort, Eastern Cooperative Group performance status (ECOGPS), tumour size and metastatic disease were independent predictors of poor survival. MVI, PSF and percentage necrosis were strongly associated with outcome but were not independent predictors of outcome. A multivariate risk model was established that incorporated six covariates (tumour size, MVI, ECOGPS, PSF, necrosis, and metastatic disease) to produce a predictive tool.

CONCLUSIONS

Both patients with localized and metastatic sRCC have very poor survival outcomes. Pathological features MVI, PSF and necrosis are important predictors of survival and could be used in a prognostic model while grade and histology do not influence prognosis. A prognostic model, if validated, could aid in patient counselling and/or clinical trial design.

Sarcomatoid conversion of clear cell renal cell carcinoma in relation to epithelial-to-mesenchymal transition

Approximately 8% of clear cell renal cell carcinoma cases contain regions of radically different morphology, demonstrating a mesenchymal appearance histologically resembling sarcomas. These biphasic neoplasms are called sarcomatoid clear cell renal cell carcinoma. Patients diagnosed with sarcomatoid clear cell renal cell carcinoma face a considerably worse prognosis due to an increased propensity for metastasis. In the present study we investigate whether the sarcomatoid conversion of clear cell renal cell carcinoma could be interpreted as linked to the process of epithelial-mesenchymal transition. Using 6 biphasic clear cell renal cell carcinoma cases we show that sarcomatoid clear cell renal cell carcinoma shares characteristic markers associated with loss of von Hippel-Lindau tumor suppressor with conventional clear cell renal cell carcinoma and also exhibits a markedly higher proliferative index. Furthermore the sarcomatoid elements demonstrate an enhanced expression of epithelial-mesenchymal transition related mesenchymal markers as compared with the clear cell renal cell carcinoma counterparts. We further selected a representative case, clinically demonstrating direct overgrowth of the sarcomatoid component into the liver and colon, for extended immunohistochemical characterization, resulting in a further set of positive and negative epithelial-mesenchymal transition markers as well as pronounced transforming growth factor β positivity, indicating that sarcomatoid clear cell renal cell carcinoma may be associated to epithelial-mesenchymal transition. Transforming growth factor β1 exposure of in vitro cultured primary clear cell renal cell carcinoma cells resulted in cells adopting a mesenchymal morphology similar to sarcomatoid clear cell renal cell carcinoma. Corresponding changes in RNA levels for key epithelial-mesenchymal transition markers were also seen. We therefore suggest that sarcomatoid clear cell renal cell carcinoma morphologically and immunohistochemically may represent a completed epithelial-mesenchymal transition and that transforming growth factor β1 could be an important driving force during the sarcomatoid transdifferentiation of clear cell renal cell carcinoma.

Expression of Snail and Slug in renal cell carcinoma: E-cadherin repressor Snail is associated with cancer invasion and prognosis

The Snail family transcription factors have been proposed as important mediators of epithelial-mesenchymal transition because of their role in down-regulation of E-cadherin and up-regulation of matrix metalloproteinases (MMPs). The present study was undertaken to investigate the expression of Snail, Slug and their associations with cancer invasion and prognosis in renal cell carcinomas (RCCs). Ninety-seven primary RCCs were analyzed for the protein expression of Snail, Slug, MMP2 and MMP9 by immunohistochemistry. Snail protein expression level was positively correlated with pathological tumor stage, histological grade and the presence of sarcomatoid carcinoma. On the contrary, Slug protein expression level was negatively correlated with pathological tumor stage, suggesting that Slug was down-regulated in advanced RCCs. Because Snail was positively associated with malignant potential of RCCs, involvement of Snail in the invasiveness of an RCC cell line 786-O was examined in the Matrigel invasion assay by down-regulating the gene expression with small interfering RNA (siRNA). Targeting the Snail, not Slug, expression in 786-O cells with siRNA caused down-regulation of the gene expression of Snail, vimentin, MMP2 and MMP9, but up-regulated the E-cadherin. Invasion of the cells through Matrigel in vitro was inhibited under this condition. Furthermore, expression levels of MMP2 and MMP9 were positively correlated with pathological tumor stage and the presence of sarcomatoid carcinoma. Statistical analysis indicated that elevated Snail, MMP2 and MMP9 protein expression are significantly worse predictors of disease-free and disease-specific survival of the patients with RCC. In conclusion, these data suggest that Snail has an important role in invasion and metastasis, and that silencing the gene may be a potential therapeutic target in RCCs.

Adult renal cell carcinoma with rhabdoid morphology represents a neoplastic dedifferentiation analogous to sarcomatoid carcinoma

Renal cell carcinoma (RCC) with rhabdoid morphology (RCC-RM) is a recently described variant of RCC, which has an aggressive biologic behavior and poor prognosis, akin to sarcomatoid RCC. The current World Health Organization classification of RCC does not include the rhabdoid phenotype as a distinct histologic entity. The aim of this study is to investigate whether RCC-RM represents a dedifferentiation of a classifiable-type World Health Organization RCC or a carcinosarcoma with muscle differentiation. We reviewed 168 cases of RCC obtained between 2003 and 2008. From these cases, 10 (6%) were found to have areas of classic rhabdoid morphology. Immunohistochemistry for cytokeratin, epithelial membrane antigen, desmin, CD10, and CD117 was performed in each case using the labeled streptavidin-biotin method. Rhabdoid differentiation was identified in association with conventional-type RCC (9) and with unclassifiable-type RCC with spindle cell morphology (1). In all cases, both the rhabdoid and nonrhabdoid tumoral areas were positive for cytokeratin and epithelial membrane antigen and negative for desmin. Cytokeratin positivity in the rhabdoid areas was focal. In cases associated with conventional-type RCC, CD10 was positive in both the rhabdoid and nonrhabdoid foci. CD117 was negative in these tumors. The unclassifiable-type RCC with spindle cell morphology was negative for both CD10 and CD117. The similar immunophenotype between the rhabdoid and nonrhabdoid tumoral foci supports the origin of the rhabdoid cells from the classifiable-type RCC. Areas of rhabdoid morphology do not represent muscle metaplastic differentiation. Renal cell carcinoma with rhabdoid morphology may represent a dedifferentiation of a classifiable-type RCC, similar to that of sarcomatoid differentiation. The recognition of RCC-RM is important as it allows for the inclusion of these high-grade malignancies into a category associated with poor prognosis despite lacking the spindle cell component classically identified as sarcomatoid change.

Dedifferentiated Endometrioid Adenocarcinoma of the Uterus

Dedifferentiation confers more aggressive malignant behaviour than would be otherwise shown by the original tumor if present alone. This phenomenon has been described in several tumors, both mesenchymal and epithelial. Dedifferentiated endometrioid carcinoma either ovarian or endometrial is the latest addition to this family of tumors. Only 2 papers have appeared in the literature so far on the topic of dedifferentiated endometrioid carcinoma, both from the same institution. We report herein a case of endometrial dedifferentiated endometrioid carcinoma in a 45-year old lady with ovarian metastasis from the undifferentiated component. The primary endometrial tumor showed an undifferentiated component in an otherwise low grade endometrioid carcinoma. The undifferentiated component of these tumors can be misdiagnosed as the solid component of FIGO grade 3 in a pure endometrioid carcinoma. The recognition of an undifferentiated component in an otherwise low grade endometrioid carcinoma is very important, since dedifferentiated endometrioid adenocarcinoma has a worse prognosis when compared with FIGO grade 3 endometrioid carcinoma.

Identifying the risk of disease progression after surgery for localized renal cell carcinoma

OBJECTIVE

To identify factors in a large cohort of patients with pathologically localized renal cell carcinoma (RCC) that predicted disease progression after surgery, as RCC most commonly presents as a localized tumour which is treated with surgical excision.

PATIENTS AND METHODS

Using an institutional database, we identified all patients who underwent radical or partial nephrectomy and had pathologically confirmed pT1 or pT2 RCC. Multivariable stepwise logistic regression analysis was used to calculate an odds ratio corresponding to the odds of progression to metastatic disease during surveillance, based on several clinical and pathological variables. We defined those variables that remained significant on multivariable analysis as risk factors and, based on the number of risk factors, we assessed risk of disease progression.

RESULTS

In all, 925 patients were eligible for analysis with a median follow-up of 48.2 months. There was progression to metastatic disease in 53 (5.7%) patients; pT1 in 20/774 (2.6%), pT2 in 33/151 (21.9%). Risk factors included pT2 disease, male gender, symptoms at presentation (local or constitutional), presence of sarcomatoid de-differentiation, and macroscopic necrosis on final pathology. In 177 patients with no risk factors, none progressed; 20 of 618 (3.2%) with one or two risk factors had progression at a median of 37.1 months; 33 of 130 (25.4%) with three or more risk factors progressed at a median of 25.2 months.

CONCLUSIONS

We identified five risk factors that can help to predict those patients with pT1 or pT2 RCC at highest risk for disease progression after surgery. The potential for disease progression is exceedingly low in patients with no risk factors and surveillance can be minimized in this group.

Three Cases of Renal Cell Carcinoma with Sarcomatoid Differentiation

Renal cell carcinoma with sarcomatoid differentiation has an incidence of 4–6%. It occurs more frequently with clinical advanced presentation in relation to the greater biological aggressiveness. This variant was also found both in transplanted kidneys and in patients with von Hippel-Lindau syndrome. The authors present three cases of cancer all clinically evolving to rapidly progressive conditions. The pathologic staging was, respectively: Case 1 pT4 NO MO G4 case, Case 2 P G4 T3a N2 MO, Case 3 pT3a N0 M1 G4. The clinical responses related to protocols with VEGF drugs that seem to have better clinical response compared to immunotherapy are still being studied. From the pathologic point of view it is necessary, for all renal cell cancers, to search and identify the sarcomatoid components that, although poorly represented, give a negative prognosis.

Percutaneous biopsy of primary tumor in metastatic renal cell carcinoma to predict high risk pathological features: comparison with nephrectomy assessment

PURPOSE

As treatment options evolve for metastatic renal cell carcinoma, there is a need for predictive information to help guide therapy. We assessed the accuracy of percutaneous primary tumor biopsy for metastatic renal cell carcinoma by comparing biopsy findings to final nephrectomy pathology in patients undergoing cytoreductive nephrectomy.

MATERIALS AND METHODS

Using an institutional database we reviewed the records of patients who underwent percutaneous primary tumor biopsy before cytoreductive nephrectomy. In patients who underwent biopsy elsewhere pathology findings were re-reviewed at our institution. Differences in accuracy based on biopsy technique, imaging modality and biopsy period were determined by chi-square analysis.

RESULTS

We identified 166 patients who underwent percutaneous biopsy of the primary tumor before cytoreductive nephrectomy between 1991 and 2007, and had data available for review. Median pathological tumor size was 9.1 cm (range 3 to 32). Median time from biopsy to surgery was 46 days (range 6 to 717). Of 104 patients in whom biopsy was assigned a Fuhrman nuclear grade 33 (31.7%) had the same grade in the nephrectomy specimen, including 74 of 109 (67.9%) when considering only high or low grade. Grade change by more than 2 points was seen in 18 of 104 patients (17.3%). Sarcomatoid features were present in 34 of 166 nephrectomy specimens (20.5%) but only 4 (11.8%) were identified preoperatively.

CONCLUSIONS

In patients with metastatic renal cell carcinoma percutaneous renal biopsy has poor accuracy to assess Fuhrman nuclear grade or sarcomatoid features. Physicians should use caution when using biopsy data to guide therapy.

Histologic evaluation of metastases in renal cell carcinoma with sarcomatoid transformation and its implications for systemic therapy

BACKGROUND

Sarcomatoid features in renal cell carcinoma may represent an aggressive subclone arising from the primary tumor. The patterns of metastases for these tumors were evaluated to determine if sarcomatoid features were retained at metastasis and whether the percentage of sarcomatoid features in the primary tumor influenced spread.

METHODS

All patients with sarcomatoid features found at nephrectomy with synchronous or metachronous resection of metastases were evaluated. The histology, grade, and percentage of sarcomatoid features in the primary and metastatic site were recorded. The association between percentage of sarcomatoid features, grade, histology, and pattern of metastases was evaluated.

RESULTS

Thirty-two patients were identified with sarcomatoid features and resected metastases. Fifty-two metastatic sites were evaluated. A single histologic appearance (sarcomatoid or carcinomatoid) was present in 50 of 52 sites (96%). Thirty sites (58%) demonstrated only a sarcomatoid pattern, whereas 20 (38%) contained only a carcinoma pattern. Histology and carcinoma grade did not influence metastatic pattern; however, greater percentage of sarcomatoid features was associated with the presence of distant sarcomatoid histology. A cutoff of 30% sarcomatoid features in the primary tumor was useful in predicting systemic sarcomatoid histology.

CONCLUSIONS

Sarcomatoid elements are frequently observed in the metastases of primary tumors with sarcomatoid features, and these metastases generally contain a solitary pattern supporting the subclone hypothesis. However, both components can metastasize in the same patient. The percentage of sarcomatoid features influences the pattern of spread, and patients with >30% sarcomatoid features in the primary tumor frequently have distant sarcomatoid histology. This cutpoint may be helpful for inclusion criteria for future clinical trials.

Cytoreductive nephrectomy for kidney cancer with sarcomatoid histology--is up-front resection indicated and, if not, is it avoidable?

PURPOSE

Cytoreductive nephrectomy has a survival advantage in select patients. Patients with sarcomatoid features are known to have poor outcomes. We reviewed the role of surgery in this population to see if these patients could be identified preoperatively.

MATERIALS AND METHODS

Cytoreductive nephrectomy cases identified as having sarcomatoid features or spindle cells were reviewed. The histology, grade, and the presence and percentage of sarcomatoid elements were recorded. Clinicopathological characteristics, survival and systemic therapy were compared to cases without sarcomatoid histology.

RESULTS

A total of 62 tumors with sarcomatoid histology were identified, accounting for 14.9% of the 417 patients undergoing cytoreductive nephrectomy. The percentage of sarcomatoid transformation widely varied with a range of 2% to 100% and a mean/median of 49.8%/50%. An increased percentage of sarcomatoid features is associated with a worse prognosis. Patients with and those without sarcomatoid features had similar clinical characteristics. In the sarcomatoid group a higher T stage (p <0.001) and increased incidence of nonclear cell histology (p <0.001) were noted. Median survival of patients with sarcomatoid features was 4.9 vs 17.7 months for nonsarcomatoid histology (p <0.001). Use of postoperative therapy was significantly worse for patients with sarcomatoid histology.

CONCLUSIONS

Patients with sarcomatoid histology undergoing cytoreductive nephrectomy have a dire prognosis despite aggressive surgery and postoperative therapy. The variability in the sarcomatoid component and the lack of specific clinical features make preoperative identification challenging. Research should focus on identifying biomarkers for this subset of tumors that may allow up-front systemic therapy with surgery reserved for responding patients.

Advances and controversies in grading and staging of renal cell carcinoma

Despite the considerable progress made in our understanding of the pathogenesis, genetics, and pathology of renal cell carcinoma (RCC), difficulties remain relating to the prediction of clinical outcome for individual cases. Although there is evidence to show that high-grade tumors have a poorer prognosis when compared to those of low grade, debate remains regarding the predictive value of grading, especially for those tumors classified into the intermediate grades. Numerous composite morphologic and nuclear grading systems have been proposed for RCC and although that of the Fuhrman classification have achieved widespread usage, the validity of the grading criteria of this classification has been questioned. In addition, there are few studies that have attempted to validate the Fuhrman system for RCCs beyond that of the clear cell subtype. Recent studies have indicated that grading of papillary RCC should be based on nucleolar prominence alone and that the components of the Fuhrman grading classification do not provide prognostic information for chromophobe RCC. Independent of tumor grade, the prognostic importance of tumor stage for RCC is well recognized. The Union Internationale Contre le Cancer/American Joint Committee for Cancer Staging and End Results Reporting TNM staging system is now in its sixth edition (2002) and recent refinements have focused on defining size cut points that will identify apparently localized tumors that will develop recurrence and/or metastases despite attempted curative surgery. In parallel with these studies it has been shown that infiltration of the renal sinus is an important prognostic factor, being observed in almost all tumors >7 cm in diameter. Questions remain as to the appropriate stratification of regional extension of RCC, as defined in the T3 tumor-staging category. Recent modifications to this category have been suggested combining the level of infiltration of the venous outflow tract with the presence or absence of infiltration of the adrenal gland and/or perirenal fat. Similarly, the utility of classifying lymph node involvement by tumor is debated, although it is well recognized that lymph node infiltration is associated with a poor prognosis. Although the current TNM classification does provide useful prognostic information it would appear that further modifications are justified to enhance the predictive value of staging for RCC.

Metastatic Sarcomatoid Renal Cell Carcinoma Treated With Vascular Endothelial Growth Factor–Targeted Therapy

Purpose

Metastatic renal cell carcinoma (mRCC) with sarcomatoid differentiation is an aggressive disease that is associated with poor outcomes to chemotherapy or immunotherapy. The utility of vascular endothelial growth factor (VEGF)–targeted therapy in patients with this disease is unknown.

Patients and Methods

Patients who had mRCC with sarcomatoid features in the primary tumor and who were treated with VEGF-targeted therapy were retrospectively identified. Pathology slides were reviewed to determine the percentage of sarcomatoid differentiation. Objective response rate, percentage of tumor burden shrinkage, progression-free survival (PFS), and overall survival (OS) were determined.

Results

Forty-three patients who had sarcomatoid mRCC were identified. The median percentage of sarcomatoid features was 14% (range, 3% to 90%). Patients were treated with either sunitinib (49%), sorafenib (28%), bevacizumab (19%), or sunitinib plus bevacizumab (5%). Partial responses were observed in eight patients (19%); 21 patients (49%) had stable disease; and 14 patients (33%) had progressive disease as their best response. Partial responses were limited to patients who had underlying clear-cell histology and less than 20% sarcomatoid elements. Median tumor shrinkage was −2% (range, −85% to 127%), and 53% achieved some degree of tumor shrinkage on therapy. Median PFS and OS were estimated to be 5.3 months and 11.8 months, respectively.

Conclusion

Patients who have mRCC and sarcomatoid differentiation can demonstrate objective responses and tumor shrinkage to VEGF-targeted therapy. Patients who have clear-cell histology and a lower percentage of sarcomatoid differentiation may have better outcomes with VEGF-targeted therapy.

Molecular and cytogenetic insights into the pathogenesis, classification, differential diagnosis, and prognosis of renal epithelial neoplasms

Renal cell carcinomas comprise a heterogeneous group of epithelial neoplasms with diverse biologic potential and variable clinical outcomes. The application of molecular and cytogenetic techniques to the study of renal neoplasms has improved our understanding of the molecular mechanisms responsible for tumor initiation and progression. Molecular classification of renal cell carcinomas has also provided new avenues for diagnosis, clinical outcome, and therapy response prediction. In this article, we review the molecular markers for various renal epithelial neoplasms and discuss the mechanisms underlying the development of these neoplasms. We also evaluate the use of molecular and cytogenetic techniques in establishing an accurate diagnosis in difficult cases and their potential usefulness in accurately classifying renal neoplasms, assessing prognosis, and selecting appropriate therapy.

Chromophobe renal cell carcinoma with neuroendocrine differentiation

Chromophobe renal cell carcinoma was described by Thoenes et al. in 1986, and associations with carcinoma of collecting ducts, conventional renal cell carcinoma and sarcomatoid renal cell carcinoma have been described. We report a case of chromophobe renal cell carcinoma which showed neuroendocrine differentiation. This is the first known case to be clearly identified as such. The patient was a 56-year-old man with constant right flank pain and hematuria; CT scan revealed an 8.5 cm nonhomogeneous mass involving the right kidney. Right radical nephrectomy was performed. The tumor showed a mixture of classical and eosinophilic patterns of chromophobe cell carcinoma. Additionally, it showed insular, glandular and rosetoid-like formations embedded in a dense eosinophilic hyaline stroma. The cells were cuboid or cylindrical with well-defined boundaries, finely stippled chromatin and a small nucleolus. The appearance of the cytoplasm varied from faintly eosinophilic to coarsely granular eosinophilic. Immunohistochemically, the neuroendocrine areas were reactive for C-kit, epithelial membrane antigen, cytokeratin, cytokeratin 7, chromogranin A, neuron-specific enolase, CD56 and S-100 protein. Our case represents a typical chromophobe carcinoma with neuroendocrine differentiation. Additionally, the immunohistochemical profile in both types of lesion suggests a common origin from renal tubular cells.

Clinical features of sarcomatoid renal cell carcinoma causing bilateral urinary tract obstruction

We report on a 52-year-old female patient hospitalized because of uremia due to bilateral urinary tract obstruction caused by bilateral sarcomatoid renal cell carcinoma (SRCC). Abdominal computed tomography with contrast showed a large mass on the left side, infiltrating the left kidney, while the right kidney was described as enlarged. The latter was investigated with sonographic angiography using contrast and selective arteriography of the renal arteries, demonstrating a pseudonodular area at the inferior pole of the right kidney. The patient underwent bilateral nephrectomy and chronic hemodialysis treatment; unfortunately, after one month she died from cachexia. To the best of our knowledge this is the first case to be reported on bilateral SRCC causing bilateral urinary tract obstruction.

Squamous differentiation in a sarcomatoid chromophobe renal cell carcinoma: an unusual case report with review of the literature

We describe an extremely rare occurrence of a squamous differentiation in a sarcomatoid chromophobe renal cell carcinoma in a 45-year-old woman with nodal and lung metastasis at presentation. The tumor on histology showed all 3 components intimately admixed with each other, which to the best of our knowledge is the first such case to be reported in the literature. The renal pelvis was smooth walled and uninvolved. Kidney-specific cadherin was positive in the chromophobe renal cell carcinoma areas and negative in the sarcomatoid and squamous areas.

Short-term effective treatment of CNS metastasis of sarcomatoid renal cell carcinoma with temozolomide and pegylated liposomal doxorubicin: A case report

Sarcomatoid renal cell carcinoma represents high-grade transformation of different subtypes of renal cell carcinoma and is associated with a dismal prognosis and high resistance to chemotherapy. We report on the course of disease of a 63 years old patient undergoing a nearly complete remission of multiple intracranial and spinal metastatic lesions of a sarcomatoid renal cell carcinoma by a combined chemotherapy with temozolomide and pegylated liposomal doxorubicin.

Overexpression of the myc target gene Mina53 in advanced renal cell carcinoma

The myc target gene Mina53 was reported to be overexpressed in esophageal cancer with a poor prognosis. The purpose of the present study was to examined Mina53 expression and its relationship to clinicopathological parameters in human renal cell carcinoma (RCC). Mina53 and Ki-67 expression was examined on immunohistochemistry for 64 surgically resected RCC and non-cancerous tissue. In addition, the relationship between Mina53 expression and clinicopathological prognostic factors of RCC such as age, stage, microvenous invasion (MVI), histological subtype, Ki-67 labeling index (LI), and prognosis, was examined. Mina53 was expressed in the nuclei of tumor cells and tubular nuclei of normal renal tissue. The expression level of Mina53 was significantly higher in patients with poor prognostic factors (stage IV, MVI-positive, and sarcomatoid RCC, and high Ki-67 LI). The prognosis of high Mina53-expressing tumors was significantly poorer than that of non-Mina53-high tumors (P < 0.0001). In conclusion, Mina53 is overexpressed in RCC tissue from patients with poor prognostic factors, suggesting that Mina53 overexpression is one of the factors for poor prognosis in RCC.

Outcome prediction for renal cell carcinoma: evaluation of prognostic factors for tumours divided according to histological subtype

A wide variety of parameters have been investigated for their prognostic significance in mixed series of renal cell carcinoma (RCC). The classification of RCC into separate types with differing morphology, genotype and probable clinical outcome has led to a re-evaluation of many prognostic parameters with studies confined to a single RCC morphotype. Tumour stage remains the most important predictor of RCC outcome and recent investigations have focused upon tumour diameter and the prognostic significance of stromal, vascular and lymphatic invasion within the renal sinus. In large tumour series, morphotype has been correlated with patient survival, with clear cell RCC being associated with a less favourable outcome than chromophobe RCC and to a lesser extent papillary RCC, for organ confined tumours. The prognostic significance of nuclear grading remains controversial. Fuhrman grading has been shown to have prognostic utility for clear cell RCC in some series. Recent studies have shown that for papillary RCC, grading should be based upon nucleolar size and that Fuhrman grading is inappropriate for chromophobe RCC. Proliferative indices based upon a variety of markers have been correlated with outcome for clear cell RCC (Ki-67, AgNORs, p21(waf1/cip1) and p27(Kip1)) and papillary RCC (Ki-67, AgNORs), although in some series prognostic significance was lost on multivariate analysis. The presence of tumour necrosis has been shown to predict survival for clear cell and chromophobe RCC, and in clear cell RCC quantification of tumour vascular density has been correlated with outcome. Several molecular markers have been investigated for prognostic significance, mostly in clear cell RCC. Although some of these markers have been shown to be significantly associated with survival, these findings remain to be confirmed in large scale follow-up studies.

The evolution of collagen expression in sarcomatoid renal cell carcinoma

The development of a sarcomatoid morphotype is recognized as an extreme form of dedifferentiation in renal cell carcinoma and is associated with a poor prognosis. Although sarcomatoid renal cell carcinoma shows pronounced spindle cell morphology, clear cell renal cell carcinoma may show early spindle cell change with cellular elongation, and the prognostic significance of this is debated. To determine the relationship between sarcomatoid renal cell carcinoma and clear cell renal cell carcinoma showing early spindle cell change, we have investigated collagen expression using immunohistochemistry in these 2 tumor types. Both sarcomatoid renal cell carcinoma and early spindle cell change tumors showed pericellular interstitial expression of collagen types I and III, whereas sarcomatoid renal cell carcinoma also showed cytoplasmic expression of these collagen types. Expression of these collagen types in typical clear cell renal cell carcinoma was, in occasional cases, limited to faint and patchy staining in a pericellular interstitial distribution. Tumor cells did not stain for collagen type IV in sarcomatoid renal cell carcinoma, early spindle cell change, or typical clear cell renal cell carcinoma. In sarcomatoid renal cell carcinoma, there was diffuse pericellular expression of collagen type V and patchy pericellular expression of collagen type VI, whereas early spindle cell change tumors showed patchy pericellular staining with antibodies to collagen type V. Collagen type VI expression in early spindle cell change was largely confined to the vascular adventitia and areas of scarring, although very occasional foci of faint interstitial staining were also seen. In typical clear cell renal cell carcinoma, staining of collagen types V and VI was limited to the vascular adventitia and foci of desmoplasia, whereas no staining of tumor cell cytoplasm were seen. This study has shown that collagen expression of sarcomatoid renal cell carcinoma differs from that of early spindle cell change and provides validating evidence that these 2 morphotypes should not be considered together for classification purposes.

Fuhrman Grading is not Appropriate for Chromophobe Renal Cell Carcinoma

This study was undertaken to assess the prognostic effectiveness of Fuhrman nuclear grading and the individual components of this grading system, in a series of chromophobe renal cell carcinomas. Eighty-seven cases of chromophobe renal cell carcinoma were investigated. There were 47 males and 40 females, 28 to 78 years of age. The carcinomas ranged from 25 to 180 mm in size and on TNM staging there were 38 stage I, 25 stage II, 22 stage III, and 2 stage IV tumors. Whole tumor Fuhrman grading was grade 1, 6 cases; grade 2, 72 cases; grade 3, 8 cases; and grade 4, 1 case, whereas focal (single high power field) grading was grade 1, 1 case; grade 2, 62 cases; grade 3, 21 cases; and grade 4, 3 cases. On assignment of nucleolar grading using Fuhrman criteria there were 37 grade 1, 44 grade 2, and 4 grade 3 tumors on whole tumor assessment and 3 grade 1, 63 grade 2, and 21 grade 3 tumors on assessment of the high power field showing the greatest degree of nuclear pleomorphism. Measurements of nuclear size showed nuclear area to range from 26.14 to 100.74 microm2, nuclear perimeter from 19.73 to 39.28 microm, and nuclear major axis from 6.49 to 13.21 microm, whereas the ranges of measures of nuclear shape were; shape factor 0.798 to 0.890, compactness 14.260 to 15.843, and feret diameter 5.694 to 11.242. Follow-up ranged from 1 to 150 months and 8 patients died of tumor-related causes 5 to 53 months from diagnosis. On log rank testing against survival, only patient age (P=0.016) and tumor maximum diameter (P=0.0055) were significant, whereas patient sex and TNM stage were not significant. Whole tumor and focal Fuhrman grading, as well as all measures of nucleolar prominence, nuclear size, and nuclear shape showed no significant association with outcome. It is concluded that neither Fuhrman grading, nor any of the components of the Fuhrman grading system, is useful as prognostic indicators for this tumor type.

Chromosomal gains in the sarcomatoid transformation of chromophobe renal cell carcinoma

The hallmark of chromophobe renal cell carcinoma is multiple chromosomal losses from among chromosomes 1, 2, 6, 10 and 17. Chromophobe renal cell carcinoma with distant metastases or sarcomatoid transformation are uncommon and little is known about their chromosomal abnormalities. We collected six sarcomatoid chromophobe renal cell carcinomas and three primary chromophobe renal cell carcinomas with distant metastases. A cytogenetic analysis by fluorescent in situ hybridization on paraffin-embedded tissue was performed using centromeric probes for chromosomes 1, 2, 6, 10 and 17. We found more than one signal in four of six (66%) sarcomatoid chromophobe renal cell carcinomas, in both sarcomatoid and adjacent epithelial components. Both primary chromophobe renal cell carcinomas and matched metastases showed single signals for all chromosomes studied in two cases and no abnormalities in the remaining case. We concluded that: (1) both epithelial and sarcomatoid components of sarcomatoid chromophobe renal cell carcinoma show different genetic abnormalities from those characteristic of chromophobe renal cell carcinoma; (2) sarcomatoid chromophobe renal cell carcinomas frequently have multiple gains (polysomy) of chromosomes 1, 2, 6, 10 and 17; (3) distant metastases show the same genetic patterns, usually chromosomal losses (monosomy), found in the primary tumors.

Renal cell carcinoma with rhabdoid features: an aggressive neoplasm with overexpression of p53

CONTEXT

Adult renal cell carcinoma (RCC) with rhabdoid features is a recently recognized morphologic variant of kidney carcinoma. To date, only very few studies have been published on this subject and p53 was not previously studied.

OBJECTIVE

To evaluate clinical attributes, morphology, and immunohistochemistry in RCC with rhabdoid component.

DESIGN

Reviewing a consecutive series of 310 RCCs, we identified 14 cases of RCC with rhabdoid features. All cases were reviewed and subjected to detailed clinical and pathologic studies with immunohistochemical evaluation of p53.

RESULTS

All tumors were clear RCCs with rhabdoid component representing from 5% to 50% of the tumor volume. Rhabdoid cells were large with a central eosinophilic intracytoplasmic inclusion and an eccentric atypical nucleus. Tumor necrosis was common (13/14) and sometimes extensive. Nine of 14 tumors were staged pT3, 4 of 14 were pT2, and only 1 tumor was pT1. On immunohistochemistry, rhabdoid cells were positive for vimentin (14/ 14), epithelial membrane antigen (11/14), and cytokeratin (9/14). Desmin and smooth muscle actin were always negative. p53 was positive in 10 of 14 tumors in the rhabdoid areas (5%-50% of tumor cells stained) but only in 5 of 14 cases in usual clear renal cell areas. In the follow-up, 10 of 14 patients developed metastases and 6 of 14 died of the disease. The median of survival was 8 months.

CONCLUSIONS

We showed that RCC with rhabdoid features is a very aggressive neoplasm with a poor prognosis. We observed an overexpression of p53 in the rhabdoid component that may be implicated in the tumor dedifferentiation.

Sarcomatoid differentiation as a prognostic factor for immunotherapy in metastatic renal cell carcinoma

BACKGROUND

The objective of the current study was to determine the significance of sarcomatoid differentiation as a prognostic factor for immunotherapy in metastatic renal cell carcinoma (RCC).

METHODS

Patients with metastatic RCC were included in this study and were categorized according to sarcomatoid differentiation.

RESULTS

Patients with sarcomatoid differentiation had more aggressive tumor characteristics than those without sarcomatoid differentiation. After immunotherapy, the median progression-free survival was 9.0 months (95% confidence interval [CI] 1.4-52.7) for patient without sarcomatoid differentiation and 3.2 months (95% CI 0.4-42.9) for patients with sarcomatoid differentiation, respectively (P=0.0001). The median overall survival was 22.2 months (95% CI 3.2-75.4) and 10.0 months (95% CI 0.7-60.1) in both groups. When comparing patients with sarcomatoid differentiation, there was no significant difference of overall survival in the immunotherapy group and the no immunotherapy group. Multivariate Cox proportional hazards model analysis showed that T stage (Hazard ratio [HR] 1.71; 95% CI 1.07-2.74; P=0.024), sarcomatoid differentiation (HR 2.18; 95% CI 1.30-3.66; P = 0.003), and the number of metastasis sites (HR 1.81; 95% CI 1.14-2.88; P=0.012) were independent predictors of progression-free survival. Sarcomatoid differentiation and the number of metastasis sites were independent prognostic predictors of overall survival. The estimated relative risks of sarcomatoid differentiation and the number of metastasis sites were 2.83 (95% CI 1.49-5.40; P=0.002) and 2.31 (95% CI 1.29-4.16; P=0.005), respectively.

CONCLUSIONS

Our findings suggest that sarcomatoid differentiation is an important prognostic factor for immunotherapy in metastatic RCC.

Cytohistopathologic hybrid renal cell carcinoma with papillary and clear cell features

Clear cell (CRCC) and papillary (PRCC) renal cell carcinomas (RCC) are the two most frequent subtypes of RCC. In this study, we studied RCC which displayed a hybrid morphology with areas of PRCC and CRCC or which contained papillary structures with clear cell changes (CCC). Consecutive cases of RCC collected over a 12-year period were reviewed to identify RCC with papillary structures and a possible admixture between CRCC and non-oncocytic PRCC. Special stains for glycogen and immunostaining for cytokeratin 7 were applied to sections containing both areas of classical PRCC and PRCC with CCC. Of the total of 541 RCC retrieved, there were 68 non-oncocytic RCC having papillary structures that could be grouped into: (a) group 1 (15 cases), CRCC with areas of papillary formation; (b) group 2a (9 cases), PRCC with extensive CCC with areas of foamy epithelial cells or macrophages; (c) group 2b (18 cases), RCC with areas of classical PRCC with focal CCC; and (d) group 3 (26 cases), RCC with features of groups 2a and 2b and containing areas of classical CRCC. There was a high rate (12/68) of sarcomatous transformation in the study cases. Groups 2 and 3 were associated with a higher rate of vascular invasion, distant metastasis, and mortality than classical PRCC and a higher rate of lymph node metastasis than CRCC. Our study identifies two groups of RCC (referred to as groups 2 and 3) that exhibit characteristic cytohistopathologic hybrid features that set them apart from classical RCC. This type of hybrid tumor seems to be associated with a more aggressive biologic behavior, and its recognition may facilitate the classification of RCC with ambiguous morphology.

Nucleolar grade but not Fuhrman grade is applicable to papillary renal cell carcinoma

This study was undertaken to determine the validity of Fuhrman grading in a series of papillary renal cell carcinomas (PRCCs), to examine the interrelationship and prognostic significance of the individual components of the grading system, and further to determine whether any observed predictive value was independent of other prognostic indicators. Ninety cases of PRCC were studied. Fifty-nine tumors were of type 1 and 31 were of type 2. There were 33 TNM stage 1, 26 stage 2, 18 stage 3, and 12 stage 4 tumors, whereas division of cases according to pT category showed 14 pT1a, 20 pT1b, 25 pT2, 15 pT3a, 4 pT3b, and 11 pT4 tumors. Ten tumors were grade 1, 58 grade 2, and 22 grade 3 when predominant Fuhrman grade was assigned, whereas grading according to the high-power field containing the highest grade (focal grade) showed 40 grade 2, 49 grade 3, and 1 grade 4 tumors. Measurements of nuclear size (area, major axis, perimeter) and shape (shape factor, compactness) were undertaken using image analysis. Nuclear area ranged from 27.63 to 116.39 microM, major axis length 6.70 to 14.06 microM, and nuclear perimeter 20.05 to 41.77 microM. Shape factor ranged from 0.805 to 0.878 and compactness from 14.33 to 15.66. Predominant nucleolar grade using the criteria of the Fuhrman classification was nucleolar grade 1 for 13 tumors, nucleolar grade 2 for 56 tumors, and nucleolar grade 3 for 21 tumors. Focal nucleolar grade based on the high-power field showing the greatest degree of nuclear pleomorphism, was grade 2 for 38 tumors and grade 3 for 52 tumors. pT category, TNM stage, focal Fuhrman grade, and PRCC type were significantly associated with survival. Of the various measures of the components of the Fuhrman classification, only focal nucleolar grade was associated with survival, on univariate analysis. On multivariate analysis, focal nucleolar grade and tumor diameter were independently associated with survival, whereas TNM stage retained significance independent of other parameters. It is concluded that assessment of nucleolar prominence rather than Fuhrman grade is applicable for stratification of tumors within TNM stage or pT category for PRCC and that this should be based upon the high-power field showing the greatest degree of nuclear pleomorphism.

Epstein-Barr virus infection in sarcomatoid renal cell carcinoma tissues

OBJECTIVE

To determine whether Epstein-Barr virus (EBV) infection is related to renal cell carcinoma (RCC) tissues.

MATERIALS AND METHODS

We investigated EBV infection and its genotypes in 73 cases of different types of RCC and 18 of non-neoplastic kidney. EBV infection and its genotypes were determined by EBV-encoded RNAs in situ hybridization (EBER-ISH) and polymerase chain reactions for EBV-encoded nuclear antigen 1 (EBNA-1) and EBNA-3C. The immunophenotype and EBV status of the EBV-infected cells were examined by double-labelling of EBER-ISH and/or immunohistochemistry for lymphoid cell markers, EBV proteins, and CD21.

RESULTS

EBER-ISH signals were detected in five of 73 RCC tissues (6.8%), but in none of 18 non-neoplastic kidneys. Interestingly, EBER-ISH was positive only in five of the 10 sarcomatoid RCCs, and of these, four also showed amplification of EBNA-1. EBV was located exclusively in the tumour-infiltrating B lymphocytes of sarcomatoid RCCs. The genotype of EBV was determined as type 1. A few EBV-infected B cells expressed BZLF1 (an EBV immediate-early gene product) while none expressed EBNA-2 or latent membrane protein 1. This indicates that the B cells are of EBV latency type I, often replicating EBV. EBV infection did not affect the survival rates of patients with sarcomatoid RCC (P = 0.635, Kaplan-Meier analysis, log-rank test).

CONCLUSION

EBV is present only in tumour-infiltrating B lymphocytes of sarcomatoid RCCs. The present study suggests that sarcomatoid RCC modulates a function of EBV-specific T cells controlling EBV replication, or stimulates differentiation of memory B cells into plasma cells.

Primary renal synovial sarcoma confirmed by cytogenetic analysis: a lesion distinct from sarcomatoid renal cell carcinoma

Primary synovial sarcoma rarely originates in the renal parenchyma. When this occurs, origin of this unusual tumor type has been the subject of debate in the literature, with a suggestion that previously reported cases may be more correctly described as renal cell carcinoma with sarcomatoid dedifferentiation. Synovial sarcoma and sarcomatoid renal cell carcinoma may be indistinguishable on pure histologic and immunohistochemical grounds, but these tumors contain distinctly different sets of chromosomal abnormalities. Most previous cases of primary renal synovial sarcoma were confirmed by molecular biology techniques, which detected the SYT-SSX gene fusion transcript typical of this tumor, but no details of the other chromosomal anomalies have been published. We report a case of primary renal synovial sarcoma confirmed by standard cytogenetic analysis, showing the characteristic t(X; 18)(p11.2:q11.2) translocation and other chromosomal aberrations that are typical of synovial sarcoma as opposed to sarcomatoid renal cell carcinoma.

SARCOMATOID RENAL CELL CARCINOMA IN A BINTURONG (ARCTICTIS BINTURONG)

An adult, female binturong (Arctictis binturong) was examined due to lethargy, inappetence, and an abdominal mass. Diagnostic investigations, including radiographs, abdominal ultrasound, clinical laboratory findings, and a fine-needle aspirate of the mass, were suggestive of a sarcoma with metastasis. Necropsy and histopathologic findings confirmed a widely disseminated sarcomatoid variant of a renal cell carcinoma, likely originating in the left kidney, with metastasis to the right kidney, spleen, pancreas, liver, mesenteric lymph nodes, and lungs. This is the first report of this neoplasm in a binturong and only the second report in the veterinary literature. Sarcomatoid renal cell carcinoma is a rare histologic variant of renal cell carcinoma that is aggressive, commonly metastatic, and associated with a very poor prognosis in humans. Accurate antemortem diagnosis of this tumor may be complicated by its biphasic morphology, which may resemble carcinoma or sarcoma (or both), often necessitating the use of immunohistochemical techniques.

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.

History of the Development of the Classification of Renal Cell Neoplasia

This article reviews the history of the development of the classification of renal cell neoplasia.

[Primary renal synovial sarcoma. A new entity in the morphological spectrum of spindle cell renal tumors]

We report 2 primary renal synovial sarcoma. These tumors were formerly designated as embryonal cystic sarcoma of the kidney. Most cases are diagnosed between the ages of 20 and 50 years. Some cases show local recurrence after nephrectomy. On gross examination, tumors are large, partially necrotic, and usually contain cysts. Microscopically, tumors are characterized by monomorphic plump spindle cells. The cysts are lined by mitotically inactive epithelial cells without striking cellular atypia. The spindle cells were immunoreactive for EMA, CD56, and sometimes for CD99. They were non-reactive for desmin, actin, S 100, and cytokeratins. The cyst epithelium is cytokeratin positive. The presence of a SYT-SSX gene fusion resulting from the t(X;18) characteristic for synovial sarcoma was demonstrated by reverse transcriptase polymerase chain reaction in both tumors. Primary renal synovial sarcoma is a distinctive tumor entity, which should be considered in renal tumors consisting of spindle cells.

Chromophobe renal cell carcinoma with sarcomatoid transformation

We present a rare case of a chromophobe renal cell carcinoma that progressed to a high-grade spindle cell sarcoma. The tumor affected a 50-year-old man who had presented with right upper quadrant discomfort and hematuria and subsequently underwent a right radical nephrectomy. Microscopically, the tumor was composed of two distinct components, a chromophobe renal cell carcinoma and a sarcomatoid component. The sarcomatoid component had exhibited aggressive behavior by spreading to a regional lymph node. This case report shows that chromophobe carcinoma can develop a sarcomatoid transformation with a high propensity for invasive growth and metastasis.

Carcinoma renal sarcomatóide: achados de imagem e anatomopatológicos. A propósito de um caso

O carcinoma renal sarcomatóide é uma neoplasia agressiva cujas características clínicas e radiológicas são similares às do carcinoma de células renais convencionais (células claras). O tumor é composto por camadas de células fusiformes malignas com aspectos imuno-histoquímicos e ultra-estruturais de células epiteliais e estromais, também podendo conter áreas mixóides de células gigantes osteoclasto-símile, células pleomórficas rabdomioblasto-símile, bem como outros componentes sarcomatóides raros. Os autores relatam um caso de carcinoma renal sarcomatóide em paciente do sexo masculino, com 54 anos de idade, apresentando a clássica tríade clínica do carcinoma de células renais. Ressaltam, também, as características macroscópicas e microscópicas típicas da lesão, e discutem os achados dos métodos de imagem e seu diagnóstico diferencial com sarcomas renais verdadeiros.

Renal cell carcinoma, chromophobe type, with collecting duct carcinoma and sarcomatoid components

We report a case of a 72-year-old man with a chromophobe renal cell carcinoma that had both sarcomatoid and collecting duct carcinoma components. The 7-cm tumor occupied the entire lower pole of the kidney and infiltrated the renal parenchyma and the pelvic-calyceal system. Histologically, it had an area of classic chromophobe renal cell carcinoma that merged into a sarcomatoid component. Closely intermixed with the sarcomatoid component was a collecting duct carcinoma component characterized by highly pleomorphic, epithelioid cells arranged in cords, nests, and tubulomicrocystic structures. The cords, nests, and tubules were associated with a florid desmoplastic stromal response and numerous inflammatory cells. In addition, dysplastic changes were noted in adjacent nonneoplastic collecting duct epithelium. Immunohistochemical studies confirmed the presence of 3 distinct components in this patient's tumor. To the best of our knowledge, this is the first reported case of a chromophobe renal cell carcinoma with sarcomatoid and collecting duct carcinoma components.

Rhabdoid differentiation of chromophobe renal cell carcinoma

AIMS

Rhabdoid change represents an aggressive form of divergent differentiation previously reported in conventional (clear-cell) and papillary renal cell carcinoma. This study aims to characterise rhabdoid differentiation in a case of chromophobe renal cell carcinoma (ChRCC) and to investigate its origin by genetic analysis.

METHODS

A large tumour mass arising in the right kidney of a 76-year-old male was investigated using routine stains (H&E, Hale's colloidal iron), immunostains (vimentin, cytokeratin) and genetic analysis for loss of heterozygosity (LOH) on chromosomes 1, 2, 3p, 6q, 10q, 13q, 17q, 17p and 21q.

RESULTS

The tumour mass was comprised of the following histological subtypes: (i) typical ChRCC, (ii) eosinophilic variant ChRCC and (iii) rhabdoid variant RCC. Tumour cells of all three different histological subtypes had a positive reaction to Hale's colloidal iron stain, negative immunostaining for vimentin and LOH on chromosomes 2, 10q, 13q and 17p. These results are consistent with a diagnosis of ChRCC and indicate a common genetic origin for all three histological cell types.

CONCLUSIONS

This study confirms that the aggressive rhabdoid variant can arise from ChRCC, as has been previously demonstrated for conventional (clear-cell) and papillary RCC.