Cytopathology of retrograde renal pelvis brush specimens: An analysis of 40 cases with emphasis on collecting duct carcinoma and low-intermediate grade transitional cell carcinoma

We report our experience with 40 retrograde renal brush samples of pelvic-calyceal lesions with confirmatory tissue studies. On-site cytopathologic evaluation was performed in 38 of these specimens. The final histologic diagnoses included 24 cases of transitional cell carcinoma (TCC), 17 of which were low-intermediate grade tumors. All 24 cases were diagnosed cytologically as TCC (22), or as suspicious for TCC (2). Three cases classified as collecting duct carcinomas were resected; the cytologic specimens in 2 of these cases were interpreted as TCC, and one as reactive change. There were three renal cell carcinomas (RCC); cytologically, one was considered a papillary neoplasm, one suspicious for malignancy, and one as reactive. Two cases of atypical renal cysts were reported as suspicious for malignancy in both cytologic and histologic material. There was one case of metastatic colon carcinoma identified in the brush specimen. Finally, tissue studies in the remaining 7 cases showed reactive/inflammatory changes; however, four of the corresponding pelvic brush specimens were considered abnormal. A review of the above cases is reported with the objective of presenting the cytologic features seen in collecting duct carcinoma, low-intermediate grade TCC, and diagnostically difficult cases with cyto/histomorphologic discrepancies. The contribution of on-site assessment to diagnostic accuracy is also discussed. Diagn Cytopathol 1996;15:312–321. © 1996 Wiley-Liss, Inc.     

Low frequency of BK virus in prostatic adenocarcinomas

BK virus (BKV) exhibits many oncogenic properties and has been associated with a variety of tumors in humans. BKV has not been well studied in the context of prostate neoplasia; however, an association of BKV with prostatic adenocarcinoma has been suggested based on the detection of viral DNA sequences and expression of viral proteins in clinical samples. To further investigate the reported association of BKV with prostatic adenocarcinoma and the potential role of the virus in prostate tumorigenesis, 30 cases of adenocarcinoma of the prostate were analyzed for evidence of BKV infection by in situ hybridization and immunohistochemistry. In situ hybridization analysis detected BKV DNA in 2 of 30 (7%) prostatic adenocarcinomas, with positive signals focally identified in less than 1% of the neoplastic cells in both cases. However, none of the tumors evaluated demonstrated evidence of BKV large tumor antigen expression by immunohistochemistry. Among prostatic adenocarcinomas that showed no evidence of BKV infection, BKV DNA was focally observed in the adjacent non-neoplastic prostate tissue in four cases by in situ hybridization in the absence of BKV large tumor antigen immunoreactivity. The findings of the present study indicate rare cases of prostatic adenocarcinoma may be associated with BKV infection. However, lack of localization of BKV to a large population of the neoplastic cells and absence of BKV large tumor antigen expression suggest that the virus does not play a role in the pathogenesis of prostate cancer.     

Transitional cell carcinoma of the bladder mimicking lobular carcinoma of the breast: a discohesive variant of urothelial carcinoma

AIMS: To describe a series of 10 cases of transitional cell carcinoma which show morphological features which mimic lobular carcinoma of the breast and diffuse carcinoma of the stomach. METHODS AND RESULTS: Ten cases were identified from the files at Southampton University Hospitals NHS Trust and from the authors' consultation files. Immunostains were performed and clinical information was obtained. Eight of the patients were male and two female. Ages ranged from 52 to 77 years at presentation. All of the tumours showed areas where the tumour was composed of uniform cells with a discohesive single-cell, diffusely invasive growth pattern. In areas the tumour cells were arranged in linear single-cell files and in separate areas solid sheets of discohesive cells. In all of the cases some tumour cells showed prominent intracytoplasmic vacuoles. In addition to this pattern, four cases showed typical transitional cell carcinoma or carcinoma in situ. The majority of the tumours expressed cytokeratin 20 but not oestrogen receptors. CONCLUSION: This study highlights a pattern of diffusely invasive transitional cell carcinoma not previously described and one which is important to recognize in order to avoid misdiagnosis of metastatic lobular carcinoma of the breast, especially in small biopsies.     

A prospective longitudinal study of BK virus infection in 120 Czech renal transplant recipients

Polyomavirus BK (BKV) is a common human polyomavirus that rarely causes clinical symptoms in immunocompetent individuals. However, BK virus reactivation occurs in 20-40% of kidney transplant patients and 1-10% of cases present with BK virus-associated nephropathy (BKVN) and reduced kidney allograft survival. In this study, 120 consecutive renal allograft recipients were monitored for BK virus replication by real-time PCR (qPCR) in the blood and urine during the first year post-transplantation and risk factors for BK viremia, viruria, and polyoma BKV-associated nephropathy were evaluated. Receiver operating characteristic curve analysis was used to determine the cutoff points for assessing the risk of developing BKVN. In total, 1,243 samples were tested. BK-DNAuria >10(7) copies/ml and BK-DNAemia >10(4) copies/ml were found in 25.8% and 5% of the samples screened, respectively, during the 12 month follow-up period. BKVN was confirmed histologically in 3/120 patients and viremic patients were treated with dialysis for longer time periods and had higher levels of panel [corrected] reactive antibodies. Patients with viruria were also treated longer with dialysis and had impaired graft function 12 months post-transplantation. Patients with sustained viruria exhibited more acute rejection episodes than patients with transient viruria. Using receiver operating characteristic curve analysis, the cutoff point for viremia and viruria was redefined to 10(3) copies/ml serum for BK viremia and a cutoff point of 6.7 × 10(7) copies/ml in urine. In conclusion, polyoma BK viremia and viruria are frequent findings in kidney transplant recipients that warrant intensive monitoring as a means of preventing graft failure [corrected].     

Multicentric papillary renal cell carcinoma associated with renal adenomatosis

A case of multicentric papillary renal cell carcinoma (RCC) associated with renal adenomatosis in the bilateral kidneys is reported. Bilateral multiple renal cysts in a 46-year-old man were pointed out incidentally by ultrasonography. Some of the left renal lesions were considered to be RCC, and left radical nephrectomy was performed accordingly. The left kidney was occupied by numerous solid nodules, which ranged from yellow to tan in color, and some of the large ones had foci of hemorrhage and necrosis. Microscopically, most of the tumors showed papillary RCC associated with renal adenoma, while others consisted only of adenomas. Ten months later, multiple lesions of the right kidney, which were initially considered to be multiple cysts, were found to have become enlarged and some of them were diagnosed as RCC. Thus, right radical nephrectomy was also performed, and these tumors showed the same features as the left renal tumors. The patient's familial history was not remarkable. The kidneys revealed various histological features, ranging from dysplastic to adenoma or carcinoma, including transitional or overlapping features between them. The findings suggest an adenoma-carcinoma sequence in papillary RCC. It is worth considering such entities.     

Mixed mesonephric adenocarcinoma and transitional cell carcinoma of the bladder

Mesonephric type adenocarcinoma is a very rare tumour in the bladder and bears a resemblance to nephrogenic adenoma. We report (to the best of our knowledge), the first case where the tumour was partly composed of mesonephric and partly of poorly differentiated transitional cell carcinoma. Staining for alpha 1-antitrypsin and carcino-embryonic antigen were positive in the mesonephric component but negative in the transitional cell carcinoma.     

Rare subtypes of BK virus are viable and frequently detected in renal transplant recipients with BK virus-associated nephropathy

BK virus-associated nephropathy (BKVN) occurs in up to 5% of kidney transplants and is a significant cause of graft loss. Four major subtypes of BKV have been described, with the vast majority of individuals persistently infected with BKV Type I (> 80% of the population). Sequencing of BKV isolates subcloned from BKVN patients revealed a high percentage of variants in the urine (40%) in the VP1 subtyping region. In vitro analysis of several viral variants revealed that all variants recovered from the urine of BKVN patients produced infectious viral particles and were replication competent in cell culture while some of the variants induced cytopathic changes in infected cells when compared to the major BKV subtype, VP1 Type I. These results suggest that rare BKV VP1 variants are more frequently associated with disease and that some variants could be more cytopathic than others in renal transplant recipients.     

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.     

肾移植术后BK病毒感染的检测及临床意义

目的 研究肾移植患者BK病毒感染的检测方法,并探讨其临床应用价值.方法 对132例两院同种异体肾移植随访患者,采集其血、尿标本进行BK病毒的检测,包括：尿沉渣decoy细胞、尿液BKV-DNA和血浆BKV-DNA,确定是否存在BK病毒复制.结果 132例肾移植患者中,37例（28.0%）尿decoy细胞阳性,出现decoy细胞阳性的中位时间为术后12个月;BK病毒尿症32例（24.2%）,中位时间为术后11个月;BK病毒血症16例（12.1%）,中位时间为术后15个月.5例BK病毒血症患者经病理学证实为BK病毒相关性肾病.结论 尿沉渣decoy细胞和体液BKV-DNA检测能早期发现BK病毒感染,为预防肾移植术后BK病毒相关性肾病提供重要的依据.     

Sclerosing TSC1 mutated renal cell carcinoma: An unusual pattern mimicking MITF family translocation renal cell carcinoma

The tuberous sclerosis genes and MTOR are increasingly being found to have important roles in novel subtypes of renal cancer, particularly emerging entities eosinophilic solid and cystic renal cell carcinoma (RCC) and high‐grade oncocytic renal tumor (HOT)/RCC with eosinophilic and vacuolated cytoplasm. We report a unique renal neoplasm in a 66‐year‐old woman that initially mimicked MITF family translocation RCC due to mixed clear and eosinophilic cells, extensive stromal hyalinization, and psammoma bodies, yet which was negative for TFE3 and TFEB fluorescence in situ hybridization and a next generation sequencing (NGS) gene fusion assay. Cytoplasmic stippling triggered consideration of TSC‐associated neoplasms, and a targeted NGS assay revealed a variant in exon 21 of TSC1 resulting in c.2626G>T p.(Glu876*) truncating mutation. This report adds to the morphologic spectrum of TSC‐related renal neoplasms, including prominent stromal hyalinization as a potentially deceptive pattern. Due to the overlap in cytoplasmic stippling between eosinophilic solid and cystic RCC and HOT/RCC with eosinophilic and vacuolated cytoplasm, it is debatable which category this example would best fit. Further understanding of these entities and other renal neoplasms with alterations in the TSC genes will elucidate whether they should be considered a family of tumors.     

Needle aspiration cytology of low-grade transitional cell carcinoma of the renal pelvis

Five cases of histologically confirmed grade 1 papillary transitional cell carcinoma of the renal pelvis investigated by needle aspiration biopsy cytology were reviewed. In all cases the needle aspirates were hypercellular. Abundant benign-appearing urothelial cells in thick clusters, in small aggregates, and singly were seen in two cases. Numerous single and loosely aggregated urothelial cells with cytoplasmic extensions and slightly pleomorphic nuclei were noted in one case. In two patients numerous urothelial fragments of variable sizes showing defined cytoplasm and mildly nuclear pleomorphism were the main cellular findings. Diagn. Cytopathol. 16:437–441, 1997. © 1997 Wiley-Liss, Inc.     

Cell heterogeneity in clear cell renal cell carcinoma

The aim of this study was to define the histological spectrum, frequency and significance of nonconventional tumour cells in clear cell renal cell carcinomas (CCRCC). Fifty‐one totally sampled CCRCC were studied histologically to evaluate the spectrum of cell morphology variability, its frequency and significance, and their correlation with tumour grade and stage, and other histological parameters of aggressive behaviour like necrosis. Aside from conventional clear/eosinophilic granular cells, three additional cellular types were identified and considered in this study: small clear cells, syncytial cells and rhabdoid cells. Small clear cells were detected in 11 cases (21.5%), syncytial cells in 8 (15.6%) and rhabdoid cells in 5 (9.8%). The presence of syncytial and rhabdoid cells statistically correlated with grade (p = 0.003 and p = 0.006) and stage (p = 0.049 and p = 0.05) in CCRCC. Necrosis correlated with stage (p = 0.018) and grade (p = 0.004), but not with syncytial, rhabdoid or small clear cells. The presence of syncytial and rhabdoid cells in CCRCC is a relatively frequent event that significantly correlates with high‐grade tumours and high stage status.     

Spindle and cuboidal renal cell carcinoma,a tumour having frequent association with nephrolithiasis: report of 11 cases including a case with hybrid conventional renal cell carcinoma/ spindle and cuboidal renal cell carcinoma components

AIMS: We present the largest series of an unclassified subtype of renal cell carcinoma, which seems to be a distinct morphological entity and which is sometimes designated as spindle and cuboidal renal cell carcinoma. METHODS AND RESULTS: Eleven cases of spindle and cuboidal renal cell carcinoma were found among 7000 primary renal cell tumours in Pilsen's routine and consultation files. The patients were five men and six women. They ranged in age from 22 to 65 years (mean 56.8). Microscopically, the tumours were composed of two main populations of cells. First, the preponderant type of cells was formed by flattened, spindle cells with sparse cytoplasm. The second cell type was a small cuboidal cell with clear to light eosinophilic cytoplasm. Spindle-shaped cells were arranged in a fascicular pattern often reminiscent of low-grade smooth muscle tumours. Solid areas of spindle cells were also present. Small cuboidal cells formed sparse tubular structures lined by a row of single cells. In addition to all previous published cases of spindle and cuboidal renal cell carcinoma we observed an association of nephrolithiasis in our cases. It was seen in 3/11 of our patients. A previously unreported feature is the occurrence of a conventional renal cell carcinoma component in one of our cases. Seven of our patients are currently well without signs of recurrence or metastasis, one had metastasis in a regional lymph node at the time of nephrectomy, one died of an unrelated condition, and two were lost to follow-up. CONCLUSIONS: We present 11 cases of spindle and cuboidal renal cell carcinoma, which is believed to be a distinctive morphological entity. Our cases were histologically, immunohistochemically and ultrastructurally similar to the previously reported cases of spindle and cuboidal renal cell carcinoma. In contrast to all previously reported cases of spindle and cuboidal renal cell carcinoma, we observed an association with nephrolithiasis in three of our cases; moreover, one of our tumours had a conventional renal cell carcinoma component and another revealed a metastatic focus in a regional lymph node. None of our patients died of the disease. This study confirms that spindle and cuboidal renal cell carcinoma has a low malignant potential.     

Mechanisms of BK virus infection of renal cells and therapeutic implications

BK virus (BKV) causes BKV nephritis in renal transplant patients and contributes significantly to the increase of probability of graft loss. BKV, being latent in the urogenital tract, is likely to be transported with the donor kidney to recipients and following reactivation replicates in the nucleus of renal epithelial tubular cells. BKV daughter viruses are released and enter other renal epithelial cells to spread infection. There are still a lot of unknown factors about the mechanism and kinetics of BKV infection. The treatment of BKV infection, with exception of reduction in immunosuppression which increases the risk of allograft rejection, is almost exclusively limited to application of anti-viral drugs with rather inconsistent results. The shortcomings of anti-viral therapies demand the understanding of early steps of infection of permissive cells by BK virus in hope that adequate interventional therapies preventing infection of cells with BK virus could be developed. This review describes the BKV entry in target human cells, intracellular trafficking pathways of BKV particles and potential therapeutic implications based on understanding of mechanisms of BKV infection of renal cells.     

Composite renal cell carcinoma and angiomyolipoma: a study of the histogenetic relationship of the two lesions

The purpose of the present study was to investigate the possible histogenetic relationship of renal cell carcinoma (RCC) and angiomyolipoma (AMYL) occurring in the same renal nodule by examining two cases of composite RCC and AMYL in patients without stigmata of tuberous sclerosis and by reviewing the medical literature of similar cases. Case 1 represents an epithelioid variant of AMYL with multiple additional nodules of typical AMYL in a surgically removed kidney. The patient subsequently developed a lesion consisting of a mixture of epithelioid variant of AMYL and RCC 24 months later in the retroperitoneum and, an additional 4 months later, in the liver. The RCC cells resembled mononucleated epithelioid cells of the epithelioid AMYL except that they were focally reactive with epithelial membrane antigen (EMA) in the retroperitoneum and focally reactive with both EMA and cytokeratin (CK) in the liver. Case 2 consisted of a typical AMYL admixed with a chromophil cell RCC. A review of the medical literature revealed seven additional cases with histopathological findings similar to this case. All cases had multiple foci of typical AMYL. Immunostaining results are available in five tumors. Chromophil RCC showed variable reactivity with CK and EMA. In addition, RCC in the two cases in the present study also displayed a positive reaction with mucin staining and a positive reactivity with carcinoembryonic antigen. There appears to be a spectrum of histopathological and immunohistochemical changes from the epithelioid variant of AMYL through a mixed epithelioid AMYL/RCC to chromophil RCC in three successive specimens in case 1. Moreover, the intimate admixture of AMYL and RCC and the similar expression of epithelial markers of RCC in the two cases in the present study, as well as other cases in the literature, suggest that some RCC develop from the same precursor cell as AMYL or from a component of AMYL.     

儿童肾细胞癌3例临床病理分析

目的：探讨儿童肾细胞癌(renal cell carcinoma,RCC)的临床病理特征、分类、诊断与鉴别诊断。方法：收集2003年~至今湖南省儿童医院3例儿童RCC病例,其中男性2例,女性1例,年龄5.5~9岁。进行光镜及免疫组化检测重新分类。结果：1例镜下以乳头状结构排列胞浆透亮的癌细胞为主,乳头间可见纤维、血管及炎细胞浸润,伴有较多钙化小体结构;其余2例镜下均以实性巢索状、腺管状排布的嗜酸性颗粒癌细胞为主,灶性区域有少量透明癌细胞排列成不典型乳头状结构,未见钙化小体;免疫组化结果：其中1例表达TFE3、Vimentin、CK-pan和CEA;第2例表达Vimentin、CK-pan、CEA及p53;第3例表达Vimentin、CK-pan、CEA、NSE、CgA、Syn及Ki-67。结论：儿童RCC较少见,HE形态下以乳头状结构排列的透明癌细胞类型需结合TFE3免疫组织化学或基因检测等手段明确诊断。术前采用静脉化疗能提高肿瘤完整切术率。儿童RCC整体预后与成人相比较好,但Xp11.2易位/TFE3基因融合相关性肾癌(Xp11 RCC)预后较透明细胞性肾细胞癌(clear cell renal cell carcinoma,CCRCC)差,由于其在儿童期多表现为惰性进展,需长期的随访观察。