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Nephrotoxicity is a rather frequent side effect of vancomycin treatment. Attributes of vancomycin nephrotoxicity (VN) are well documented, including its clinical manifestations and renal morphologic changes. However, VN has not been emphasized as the cause of acute kidney injury (AKI) in the renal transplant setting. We report the first 3 such cases. In each of these cases, AKI developed concurrently with vancomycin treatment and resolved after its cessation. As compared with the general population, VN in the renal transplant setting displayed some unusual clinical behaviors. Its development was rather capricious, being noted in some but not every episode of vancomycin treatment, even in the same individual. AKI developed gradually in conjunction with protracted vancomycin treatment, in contrast to a precipitous course in the nontransplant setting. However, renal transplant biopsies showed typical features of VN in each case. VN is an unusual but now well-documented cause of AKI in renal transplant recipients. VN in this setting may display some atypical features, setting it apart from that in the general population. However, renal transplant biopsy changes are characteristic and are amenable to a definitive diagnosis.

Background: Systemic lupus erythematosus (SLE) represents a principal prototype of a multisystemic autoimmune disease with the participation of both cell- and antibody-mediated mechanisms causing significant renal impairment. A renal biopsy diagnosis is the gold standard for clinical renal disease in SLE, which includes a broad range of indications. Summary: Renal disease in SLE can involve glomerular, tubulointerstitial, and/or vascular compartments, none of which are mutually exclusive. In most instances, the basic pathogenetic mechanism involves tissue deposition of immune complexes and/or cell-mediated mechanisms, identified by light microscopy, immunohistochemical methods, and electron microscopy (EM), evoking intraglomerular proliferative, inflammatory, and other tissue responses. These produce a spectrum of histologic lesions, depending on the participation of a wide range of clinical triggers, namely, genetic, serological, and immunological factors, correlating with their underlying pathogenetic potential. In addition to light and immunofluorescence microscopy, EM in this setting facilitates an accurate diagnosis, assesses disease activity, delineates subclasses, differentiates from primary forms of non-lupus renal lesions, identifies organized deposits, and rarely, identifies other forms of nonimmune complex lesions such as podocytopathies, amyloidosis, and thrombotic microangiopathy. Key Messages: EM findings that are distinctive for most of the renal lesions in SLE include immune complex and nonimmune complex diseases as well as overlapping entities. Routine ultrastructural examination not only provides significant diagnostic and prognostic information from both initial and repeat renal biopsies from lupus patients but also contributes toward the understanding of the underlying pathophysiology of the disease process.

Introduction Vancomycin nephrotoxicity is frequent and may be due to drug-induced acute tubular necrosis (ATN) or tubulointerstitial nephritis (TIN). Vancomycin-associated tubular cast (VTC) was recently described and may represent a novel cause of vancomycin nephrotoxicity. However, much is still unknown about VTC. Materials and Methods Thirty-seven kidney biopsy specimens from patients who were treated with vancomycin and developed acute kidney injury (AKI) were found among a total of 4673 biopsy samples between 2010 and 2019. These biopsy specimens were subjected to light microscopy, immunofluorescence, electron microscopy, and immunolocalization for vancomycin, uromodulin, myoglobin, tubular segment–specific markers, and examined for VTCs. The findings were correlated with the clinical course. Results VTCs displayed precipitated vancomycin casts in a background of uromodulin; the casts were limited to the distal tubules, and always associated with a background of more diffuse renal injury (ATN or TIN). The diagnosis of vancomycin nephrotoxicity was made in in 28 of 37 patients. VTC was noted in 25 of 28 biopsy samples from patients diagnosed with vancomycin nephrotoxicity and in one of nine biopsy samples from patients without this diagnosis. Vancomycin nephrotoxicity was diagnosed in 25 of 26 patients whose biopsy specimens showed VTC, but in only 3 of 11 patients without VTC in the biopsy samples. Conclusions VTC displays a characteristic morphologic profile amenable to ready recognition in biopsy specimens. It results from coprecipitation of vancomycin and uromodulin. It facilitates the biopsy diagnosis of vancomycin nephrotoxicity. It may have a nephrotoxic effect superimposing on and independent from the ATN or interstitial nephritis in the pathogenesis of vancomycin nephrotoxicity., Graphical abstract

Introduction Incidental IgA deposits in donor kidneys have unknown sequelae and may predate clinical kidney disease if primed by adverse immunologic or hemodynamic stimuli or may remain dormant. Methods The presence of incidental IgA in post-implantation (T0) biopsies from living (LDK) and deceased donor (DDK) kidneys, and its relationship to post-transplant patient and graft outcomes was investigated in an ethnically diverse US population at a large transplant center. Results Mesangial IgA was present in 20.4% of 802 T0 biopsies; 13.2% and 24.5% of LDK and DDK, respectively. Donors with incidental IgA deposits were more likely to have hypertension and be of Hispanic or Asian origin. Intensity of IgA staining was 1+ (57.3%), 2+ (26.8%), or 3+ (15.8%) of the T0 IgA+ biopsies. Mesangial pathology correlated with higher-intensity IgA staining with less clearance on follow-up (53.8%) versus 79.2% without mesangial pathology. IgA cleared in 91%, 63%, and 40% of follow-up biopsies with 1+, 2+, and 3+ IgA staining, respectively. Early post-transplant rejection and rejection-related graft loss occurred more frequently in IgA+ kidney recipients; however, 5-year kidney function and graft survival were comparable to kidneys without IgA. Conclusion This first and largest report of incidental IgA in T0 biopsies of LDK and DDK in a US ethnically diverse population demonstrated no adverse association between the presence of IgA in donor kidneys and graft or patient survival. Whether IgA in donor kidneys represents latent IgA nephropathy (IgAN) is uncertain; nevertheless, living donors who demonstrate IgA on T0 biopsy deserve careful follow-up., Graphical abstract

We herein report a 46-year-old man with diabetes who developed acute kidney injury and oliguria after receiving vancomycin to treat his foot infection. Renal biopsy revealed typical features of advanced diabetic nephropathy as well as features of acute vancomycin nephrotoxicity. Several changes typical for acute vancomycin nephrotoxicity, but hitherto not adequately described, were seen. There was an element of acute tubulointerstitial injury associated with frequent tubular casts consisting of typical hyaline casts, pale glassy material suggestive of uromodulin, and distinctive features suggestive of vancomycin deposition. Coprecipitation of vancomycin and uromodulin was confirmed by immunostain. Electron microscopic study showed features supportive for the diagnosis of diabetic nephropathy and distinctive concentric appearance of vancomycin tubular casts within the fibrillary background of uromodulin. The patient’s renal function improved rapidly after cessation of vancomycin and initiation of steroid therapy, suggesting that vancomycin-associated tubular injury is potentially reversible over time with proper management.

Lupus nephritis is a common manifestation of systemic lupus erythematosus (SLE). IgA nephropathy is a common type of primary glomerulonephritis. Renal manifestations in SLE patients are often due to lupus nephritis; however, renal diseases unrelated to lupus nephritis are rarely reported. While crescentic IgA nephropathy with rapid clinical progression is rare, its development in patients with SLE in the absence of lupus nephritis is even more unusual. A 74-year-old woman with a history of SLE without known renal involvement, chronic kidney disease stage IIIa, congestive heart failure, hypertension, and type 2 diabetes mellitus presented with acute kidney injury. Her creatinine continued to rise rapidly. Renal biopsy revealed mesangial proliferative glomerulonephritis with crescent formation. Immunofluorescent staining showed IgA and C3 mesangial deposition and absence of C4 and C1q, consistent with IgA nephropathy. She received a course of methylprednisolone and plasmapheresis. Unfortunately, her renal function continued to deteriorate, and she was started on hemodialysis which was continued after hospital discharge. This case illustrates crescentic IgA nephropathy without lupus nephritis as the cause of acute kidney injury in a patient with SLE. It highlights the observation that renal diseases other than lupus nephritis can develop in SLE patients.

Chronic kidney disease (CKD) induces the failure of arteriovenous fistulas (AVFs) and promotes the differentiation of vascular adventitial GLI1-positive mesenchymal stem cells (GMCs). However, the roles of GMCs in forming neointima in AVFs remain unknown. GMCs isolated from CKD mice showed increased potential capacity of differentiation into myofibroblast-like cells. Increased activation of expression of PDGFRA and hedgehog (HH) signaling were detected in adventitial cells of AVFs from patients with end-stage kidney disease and CKD mice. PDGFRA was translocated and accumulated in early endosome when sonic hedgehog was overexpressed. In endosome, PDGFRA-mediated activation of TGFB1/SMAD signaling promoted the differentiation of GMCs into myofibroblasts, extracellular matrix deposition, and vascular fibrosis. These responses resulted in neointima formation and AVF failure. KO of Pdgfra or inhibition of HH signaling in GMCs suppressed the differentiation of GMCs into myofibroblasts. In vivo, specific KO of Pdgfra inhibited GMC activation and vascular fibrosis, resulting in suppression of neointima formation and improvement of AVF patency despite CKD. Our findings could yield strategies for maintaining AVF functions., Hedgehog signaling regulates PDGFRA in vascular adventitial mesenchymal stem cells to promote neointima formation in arteriovenous fistula in chronic kidney disease.

We report a colonic adenocarcinoma associated with diffuse submucosal deposition of a peculiar spheroid-type amyloid identified in the colon, terminal ileum, and appendix. A 65-year-old woman with past medical histories of hypertension, and chronic obstructive pulmonary disease, presented to the emergency room with cramping abdominal pain and nausea. A computed tomography (CT) scan of abdomen showed right colonic volvulus. Emergency right hemicolectomy was performed. The specimen showed colonic adenocarcinoma with focal submucosal invasion (pT1) arising from a villotubular adenoma. A diffuse submucosal spheroid-type amyloid deposition (resembling corpora amylacea-like structures with Liesegang ring formation) was identified in the colon, ileum, and appendix. Electron microscopy examination of this unusual spheroidal-type material further confirmed the presence of amyloid fibrils. Analysis by liquid chromatography-mass spectrometry detected AL (lambda) type amyloidosis in this specimen. Tests for monoclonal gammopathy were not performed because patient consent was not obtained. In tissue section evaluation, however, no plasma cell neoplasm was identified. Cases with isolated AL amyloid deposition in the gastrointestinal tract have been reported rarely, and there is no case report of colonic adenocarcinoma associated with primary amyloid deposition in the English literature.

Nonneoplastic renal changes are frequent in nephrectomy specimens for tumor. These changes display a wide morphologic and diagnostic range. They often carry profound clinical implications, but are often underappreciated or even ignored. The renal tissue is normal in about 10% of cases. Among the remainders, arterionephosclerosis and diabetic nephropathy account for the majority. These two diseases also account for most of the clinical significance of the nonneoplastic renal changes and their severity correlates with the renal outcome. A large number of other “medical” renal diseases are also encountered, albeit much less frequently. Their morphology is similar to that of their sporadic counterparts, and perhaps so is their clinical behavior. Large renal cell neoplasms, especially those which are centered in renal medulla or urothelial carcinoma, may be associated with changes in nonneoplastic renal parenchyma due to urine obstruction. Kidneys with end-stage renal disease (ESRD) can give rise to renal cell carcinoma directly, or through an intermediate phase characterized by cystic tubular changes aptly termed acquired cystic kidney disease (ACKD). Thus, ESRD alone or with ACKD is increasingly recognized in nephrectomy specimens for renal tumors. Renal tumors of specific histologic types can be a component of several hereditary syndromes. Several distinctive lesions can develop in the nonneoplastic renal tissue in this context. This chapter details these above changes.

Hereditary renal cell carcinomas (HRCC) comprise about 2–4% of all renal cell carcinomas (RCC). With understanding of molecular basis of RCC, 10 HRCC syndromes have been recognized. All of them exhibit an autosomal dominant inheritance pattern. More common and well-known HRCC syndromes are von Hippel–Lindau (VHL), hereditary papillary RCC, Birt–Hogg–Dube syndrome (BHD), hereditary leiomyomatosis RCC (HLRCC) syndrome, and tuberous sclerosis.

Renal cell carcinoma constitutes 90% of all kidney cancers. Familial/genetic cause accounts for 2–4% of the cases and the rest of them are sporadic. The classification of renal cell carcinoma has been expanded since the first Heidelberg classification in 1997. The recently published 2016 World Health Organization classification has revealed several renal cell carcinoma subtypes according to the molecular and morphological investigations. The complex molecular changes underlying renal cell carcinoma variants and the corresponding familial cancer syndromes still remain the subject of ongoing investigations, especially for the mechanism-based therapeutic approaches. In this section, the molecular pathways and molecular features of each renal cell carcinoma subtype and the corresponding hereditary forms are reviewed.

Deceased diabetic kidneys are increasingly utilized in transplantation. The relationship of donor's history of diabetes to clinical and histological outcomes was examined. Forty-nine diabetic deceased donor kidneys (D-DM) were transplanted into 26 normal (R-N/D-DM) and 23 diabetic recipients (R-DM/D-DM) and compared to 211 diabetic recipients of normal kidneys(R-DM/D-N) and 466 normal recipients of normal kidneys (R-N/D-N). Patient survival at 5 years was 89.7% in R-N/D-N, 96.2% in R-N/D-DM, 80.1% in R-DM/D-N, and a 71.6% in R-DM/D-DM (P = .008). Death-censored graft survival at 5 years was 86.3% in R-N/D-N, 87.4% in R-N/D-DM, 93.5% in R-DM/D-N, and 87.5% in R-DM/D-DM (P = .24). Multivariable regression analysis showed that compared to non-diabetic recipients, diabetic recipients had a 2- to 3-fold increased risk of mortality. In this cohort, there was no impact on death-censored graft survival of diabetic donor status. Only 6 of 26 post-perfusion biopsies showed evidence of diabetic nephropathy (

Renal transplantation is an ever-growing therapeutic option for patients with end-stage renal disease due to lupus nephritis. Outcomes for these patients are comparable to those of patients receiving renal transplantation for other causes. A known complication for these patients is recurrence of lupus nephritis in the renal graft (recurrent lupus nephritis [RLN]). Although disease severity at the time of recurrence is usually milder, a small number of cases have been reported to progress to allograft failure. There is a trend toward preemptive renal transplantation in patients with lupus nephritis, as more favorable outcomes have been observed with this treatment modality. While clinicians usually seek clinical remission of lupus prior to proceeding with renal transplantation, no guidelines are established regarding how often to check for serologic activity of lupus in patients with end-stage renal disease due to lupus nephritis and whether these serologic markers should be taken into account when deciding on the timing of transplantation. We present a case of early RLN co-occurring with acute cellular rejection 15 days after renal transplantation. The patient had been in clinical remission for more than 5 months prior to transplantation but had a rise in anti–double-stranded DNA antibody titers and a decrease in complement C3 level at the time of surgery. Although additional studies are needed to establish the extent to which serologic markers of lupus correlate with renal graft dysfunction, this case suggests hypocomplementemia and high double-stranded DNA antibody titers may be a risk factor for early RLN.

The value of histochemical analysis in the diagnosis of medical renal diseases has long been known, and its use continues currently. Depending on the particular disorder in question, a variety of "special" stains may be applied to renal biopsies. These include the periodic acid-Schiff, Masson trichrome, Jones, von Kossa, Verhoeff-van Gieson, Congo Red, and toluidine blue methods, among others. This review considers the application of such techniques in the assessment of vascular, glomerular, and tubulointerstitial lesions of the kidney.

Summary Knowledge on renal involvement in kidney donors with diabetes, that is, diabetic nephropathy (DN), is limited. During the 7 years (2010-2017), 921 postperfusion biopsies were performed for living donors (14%) or deceased donors (86%). The Renal Pathology Society classification schema for DN (class 0-IV) was used. Biopsies with light microscopic changes of DN (at least class IIa) were selected for study. Eleven biopsies (1.2%) showed DN, all from deceased donors (class IIa in 8, class IIb in 2, and class III in 1 biopsy). The glomerular basement membrane thickness ranged from 439 ± 52 to 725 ± 82 nm. These biopsies also displayed arterionephrosclerosis. They were from 9 deceased donors (fulfilling clinical criteria for acceptance in all, diabetes ;[>6 years] in 8, hypertension in 6, and proteinuria [1+] in all). Follow-up biopsies (5-342 weeks after transplant) showed DN of the same class (7 biopsies), probably progression (1), or progression (3). At follow-up (15-416 weeks), all recipients were alive. One graft was lost at 76 weeks because of progressive DN. The other 10 grafts were functioning, but the serum creatinine reached 2.0 to 2.7 mg/dL in 5 of them. Although diabetes is frequent in kidney donors, donor-related DN is unusual. It is observed only in deceased donors, but the risk factors for its development are not known. Donor-related DN may be stable or progress. Whether it resolves, especially for DN in early phase, remains unknown. It may adversely impact the graft outcome with a magnitude proportional to the severity of the tissue injury in the postperfusion biopsies.

HIV-positive individuals are at increased risk for kidney disease, including HIV-associated nephropathy, non-collapsing focal segmental glomerulosclerosis, immune-complex kidney disease, and comorbid kidney disease, as well as kidney injury resulting from prolonged exposure to antiretroviral therapy or from opportunistic infections. Clinical guidelines for kidney disease prevention and treatment in HIV-positive individuals are largely extrapolated from studies in the general population, and do not fully incorporate existing knowledge of the unique HIV-related pathways and genetic factors that contribute to the risk of kidney disease in this population. We convened an international panel of experts in nephrology, renal pathology, and infectious diseases to define the pathology of kidney disease in the setting of HIV infection; describe the role of genetics in the natural history, diagnosis, and treatment of kidney disease in HIV-positive individuals; characterize the renal risk-benefit of antiretroviral therapy for HIV treatment and prevention; and define best practices for the prevention and management of kidney disease in HIV-positive individuals.

With the increasing utility of hematopoietic stem cell transplantation (SCT) as a treatment for cancer and noncancerous disorders, more challenges and complications associated with SCT have emerged. Renal injury immediately after transplant is common and well understood, but long-term renal injury is becoming more evident. Chronic graft-versus-host disease (GVHD) is a known long-term complication of SCT, and membranous nephropathy (MN) is emerging as the most common cause of SCT-associated glomerular pathology. In this case report, we present a patient who developed features of anti-PLA2R antibody-negative MN following autologous SCT. The renal injury responded well to steroids and further response to rituximab therapy was noted, suggesting antibody-mediated autoimmune glomerular disease. We also present a review of the literature on autologous GVHD and the role of T and B cells in induction of autoimmunity by SCT.

We determined the likelihood that transurethral resection biopsy of the prostatic urethra adjacent to the verumontanum would detect prostatic involvement of urothelial carcinoma in patients with bladder carcinoma.We compared precystectomy transurethral resection biopsy specimens of the prostatic urethra with those of the matched radical cystoprostatectomy in 272 patients with urothelial carcinoma of the bladder. All prostates were evaluated by whole mount step sections.Prostatic involvement by urothelial carcinoma was detected by transurethral resection biopsy or radical cystoprostatectomy in 101 patients (37.1%). Transurethral resection biopsy detected urothelial carcinoma in 72 cases with 71.3% sensitivity and 100% specificity. The overall accuracy of transurethral resection biopsy to detect urothelial carcinoma of the prostate was 89% (positive and negative predictive values 100% and 86%, respectively). Invasive prostatic urothelial carcinoma arising from the prostatic urethra was detected by transurethral resection biopsy in 21 of 26 patients (81%) while prostatic carcinoma in situ was detected in 39 of 52 (75%). Transurethral resection biopsy detected prostatic invasive urothelial carcinoma resulting from transmural invasion of a bladder tumor in 4 of 15 patients.Prostatic involvement by urothelial carcinoma of the bladder was found in 37.1% of patients. Transurethral resection biopsy missed most tumors resulting from transmural invasion of the bladder primary lesion. Carcinoma in situ and invasive urothelial carcinoma arising from the prostatic urethra were detected in most cases. Transurethral resection biopsy of the prostatic urethra can complement staging and support clinical decision making with respect to neoadjuvant chemotherapy and planning for an orthotopic neobladder.

Sarcoid-like (SL) granulomas have been previously described in association with malignant tumors. These granulomas appear to be tumor-related but are not indicative of systemic sarcoidosis, and hence are referred to as SL reactions. These SL reactions can be seen within the primary tumor, its vicinity, or in uninvolved sites such as the spleen, bone marrow, skin, and/or regional lymph nodes draining the tumor. It is a widely held view that SL granulomas are caused by soluble antigenic factors, shed by tumor cells or released due to tumor necrosis. SL reactions reported in Hodgkin lymphoma have been associated with a better prognosis. SL granulomas are thought to play an important role in the host's defenses against metastatic extension. SL granulomas have been reported in approximately 4.4% of carcinomas. Isolated cases of renal cell carcinoma (RCC) with SL granulomas have been reported with questionable prognostic significance. We identified 11 cases of RCCs with SL granulomas. Interestingly, all cases had abundant clear cell cytoplasm (10 clear cell RCC cases and 1 clear cell papillary RCC). We propose that this clear, abundant cytoplasm of the tumor cells with high content of glycogen and lipids may trigger granuloma formation akin to that seen in seminomas with SL granulomas. To date, this is the largest case series of RCCs with SL granulomas.

Mesoamerican nephropathy is a devastating disease of unknown etiology that affects mostly young agricultural workers in Central America. An understanding of the mechanism of injury and the early disease process is urgently needed and will aid in identification of the underlying cause and direct treatment and prevention efforts. We sought to describe the renal pathology in Mesoamerican nephropathy at its earliest clinical appearance in prospectively identified acute case patients in Nicaragua. We considered those with elevated (or increased at least 0.3 mg/dL or 1.5-fold from baseline) serum creatinine, leukocyturia, and either leukocytosis or neutrophilia for inclusion in this biopsy study. Renal tissue was obtained by ultrasound-guided biopsy for examination by light, immunofluorescence, and electron microscopy. All 11 individuals who underwent renal biopsy showed tubulointerstitial nephritis, with varying degrees of inflammation and chronicity. Interstitial cellular infiltrates (predominantly T lymphocytes and monocytes), mostly in the corticomedullary junction; neutrophilic accumulation in the tubular lumens; largely preserved glomeruli; few mild ischemic changes; and no immune deposits were noted. The acute components of tubulointerstitial nephritis were acute tubular cell injury, interstitial edema, and early fibrosis. Chronic tubulointerstitial nephritis included severe tubular atrophy, thickened tubular basement membrane, and interstitial fibrosis. Thus, renal histopathology in Mesoamerican nephropathy reveals primary interstitial disease with intact glomeruli.

Despite dose-limiting nephrotoxic potentials, polymyxin B has reemerged as the last line of therapy against multidrug-resistant Gram-negative bacterial infections. However, the handling of polymyxin B by the kidneys is still not thoroughly understood. The objectives of this study were to evaluate the impact of renal polymyxin B exposure on nephrotoxicity and to explore the role of megalin in renal drug accumulation. Sprague-Dawley rats (225 to 250 g) were divided into three dosing groups, and polymyxin B was administered (5 mg/kg, 10 mg/kg, and 20 mg/kg) subcutaneously once daily. The onset of nephrotoxicity over 7 days and renal drug concentrations 24 h after the first dose were assessed. The effects of sodium maleate (400 mg/kg intraperitoneally) on megalin homeostasis were evaluated by determining the urinary megalin concentration and electron microscopic study of renal tissue. The serum/renal pharmacokinetics of polymyxin B were assessed in megalin-shedding rats. The onset of nephrotoxicity was correlated with the daily dose of polymyxin B. Renal polymyxin B concentrations were found to be 3.6 ± 0.4 μg/g, 9.9 ± 1.5 μg/g, and 21.7 ± 4.8 μg/g in the 5-mg/kg, 10-mg/kg, and 20-mg/kg dosing groups, respectively. In megalin-shedding rats, the serum pharmacokinetics of polymyxin B remained unchanged, but the renal exposure was attenuated by 40% compared to that of control rats. The onset of polymyxin B-induced nephrotoxicity is correlated with the renal drug exposure. In addition, megalin appears to play a pivotal role in the renal accumulation of polymyxin B, which might contribute to nephrotoxicity.

Congo red stain apple-green birefringence under polarized light is the most popular method for detecting amyloid; however, it has limitations. The goal of this study was to evaluate if examination of Congo red stain by fluorescent microscopy (FM) significantly enhances the diagnostic yield. Congo red-stained tissue sections were retrospectively and prospectively examined by light microscopy (LM) with and without polarizer and by FM using the Texas red filter and results by each method compared. Congo red-stained amyloid recognized by LM was unequivocally and easily identified by FM in each of 48 cases. In 22 of them, FM either confirmed the presence of a small amount of amyloid or lead to a definitive diagnosis, which was otherwise missed. Eight cases with Congo red-negative by LM were also negative by FM. In 8 cases with a false-positive Congo red stain, FM still detected the signal in 5, but it was absent in 3 cases. In conclusion, Congo red fluorescence improves the diagnostic yield of LM for both positive and negative cases.

Objective: It was the aim of this study to determine the utility of PAX2 and PAX8 in cytology effusions with metastatic tumor. Study Design: PAX2 and PAX8 immunohistochemical staining was performed on cell blocks of 89 pleural, pericardial and peritoneal effusions with benign diagnoses (18 cases), or secondary to renal cell carcinoma (RCC; 9 cases), müllerian carcinoma (21 cases) or non-müllerian carcinoma (41 cases). Results: PAX2 stained 0% (0/18) of controls, 100% (8/8) of RCCs, 35% (7/20) of müllerian carcinomas, and 2% (1/41) of non-müllerian carcinomas. PAX8 stained 6% (1/18) of control cases, 100% (9/9) of RCC cases, 100% (20/20) of müllerian carcinomas, and 5% (2/41) of non-müllerian carcinomas. PAX2 was 35% sensitive and 95% specific for müllerian carcinoma and 100% sensitive and 95% specific for RCC. PAX8 was 100% sensitive and 95% specific for müllerian carcinoma and 100% sensitive and 95% specific for RCC. Conclusions: PAX8 is more sensitive than PAX2 for metastatic effusions from müllerian carcinomas (100 vs. 35%), while also having a higher intensity of staining than PAX2. However, PAX2 and PAX8 are both highly sensitive and specific for RCCs. PAX2 and PAX8 are valuable diagnostic markers for metastatic müllerian carcinomas and RCCs in effusion cytology. PAX8 is superior for carcinomas of müllerian origin.

Background. Cancer patients are particularly vulnerable to drug-induced kidney injury during their chemotherapy. Whereas the direct nephrotoxic effects of these drugs are well recognized, that of tubulointerstitial nephritis (TIN) is less well known, underdiagnosed and often reported only as a functional tubular disorder. The diagnosis of acute TIN is important because of its insidious onset with tubular dysfunction, its potential reversibility if detected early and the possibility of its response to steroid treatment. Methods. We performed a literature review (44 cases) and reviewed our institutional biopsy register (12 cases) of patients on cancer chemotherapy with documented TIN. Biopsies were considered in three groups: acute TIN, chronic TIN and acute on chronic TIN. The outcomes that were evaluated were recovery of kidney function, development of chronic kidney disease and onset of end-stage renal disease (ESRD). Results. Ifosfamide, BCG, tyrosine kinase inhibitors and premetrexed were the most commonly implicated drugs. Ifosfamide and premetrexed were associated with worst outcomes. Recovery of kidney function was better in acute TIN (ATIN) (29%) with fewer progressing to ESRD (12.9%) than with chronic TIN (7.6% recovery, 15.3% ESRD). Steroid use appeared to favorably alter outcomes in ATIN (40% recovery) compared with conservative treatment (18.75% recovery). Peak serum creatinine, age, gender and type of malignancy did not influence outcomes. Conclusions. As a potentially reversible lesion that can respond to withdrawal of the suspected agent, and in some cases to a short course of steroid therapy, it is important to consider ATIN in the differential diagnosis of all cases of acute kidney injury in cancer patients on chemotherapy.

Hemodialysis patients depend on arteriovenous fistulas (AVF) for vascular access. Unfortunately, their 2-yr primary patency rate is only 60% because of AVF clog due to intimal hyperplasia at the venous anastomosis. Chronic kidney disease (CKD) can increase neointima formation by unknown mechanisms. A new AVF mouse model was created, and the mechanisms of CKD on neointima formation in AVFs were investigated. We created AVFs in mice by anastomosing the common carotid artery to the internal jugular vein. CKD was induced [BUN (blood urea nitrogen) in control and CKD mice, 33.3 ± 3.9 vs. 114.2 ± 12.1 mg/dl, P < 0.05]. After 1 day, there was endothelial cell loss and CD41-positive platelet aggregation, especially in the venous anastomosis. An invasion of macrophages and neutrophils peaked at 1 wk after surgery. Neointima formation (smooth muscle cell accumulation and extracellular matrix deposition) increased progressively over 4 wk. Mice with CKD had ∼45% ( P < 0.05) more neointima formation than control mice. CKD decreased vascular endothelial-cadherin expression in endothelial cells and delayed regeneration of the endothelium. CKD also increased inflammatory cells (Mac-2-positive or CD45-positive) in AVFs at 2 wk. Finally, AVFs were “leakier” (increased accumulation of Evans blue) in CKD mice at 7 and 14 days than control mice. We find that CKD increases neointima formation and endothelial barrier dysfunction. We have created a mouse model of AVF with characteristics similar to failed AVFs in patients. The model will allow testing of strategies directed at improving AVF function in CKD patients.

Nephrogenic adenoma is a benign lesion of the urinary tract, particularly the urinary bladder. It is a gross and microscopic mimicker of urothelial neoplasm or metastatic carcinoma. Several histological patterns (tubular, tubulocystic, polypoid, papillary, fibromyxoid) have been recognized, but a flat pattern has not been described. Histologically, nephrogenic adenoma consists of tubules, cysts or papillae lined by flat to polygonal cells with frequent hobnail appearance. The stroma is often edematous or has a granulation tissue-like appearance with acute or chronic inflammation. By immunohistochemistry, nephrogenic adenomas are positive for renal epithelial markers CK7, CD10 and alpha-methylacyl-coenzyme A racemase, and negative for bladder urothelium or prostate markers. Recent studies have shown that nephrogenic adenomas are positive for PAX2 and PAX8. We encountered an interesting case of tubular nephrogenic adenoma with adjacent areas suspicious of flat urothelial atypia. Immunohistochemistry for PAX2 and PAX8 were positive in these areas, unveiling a flat pattern of nephrogenic adenoma. This case prompted us to study 15 cases of nephrogenic adenoma to determine additional instances of flat pattern and to assess the value of PAX2 and PAX8 immunoreactivity to diagnose nephrogenic adenoma. PAX2 and PAX8 immunostaining was positive in 14/15 and 15/15 cases, respectively. The flat pattern was present at least focally adjacent to tubular, polypoid and papillary areas, in 8/15 cases of nephrogenic adenoma. In conclusion, the flat pattern is a common finding in nephrogenic adenomas, but easily under recognized by morphologic examination and may be confused with flat urothelial lesions with atypia. Immunostains for PAX2 and PAX8 are useful in the detection of nephrogenic adenomas and particularly unveil those nephrogenic adenomas with flat pattern.

How the kidney responds to the metabolic cues from the environment remains a central question in kidney research. This question is particularly relevant to the pathogenesis of diabetic nephropathy (DN) in which evidence suggests that metabolic events in podocytes regulate chromatin structure. Here, we show that miR-93 is a critical metabolic/epigenetic switch in the diabetic milieu linking the metabolic state to chromatin remodelling. Mice with inducible overexpression of a miR-93 transgene exclusively in podocytes exhibit significant improvements in key features of DN. We identify miR-93 as a regulator of nucleosomal dynamics in podocytes. miR-93 has a critical role in chromatin reorganization and progression of DN by modulating its target Msk2, a histone kinase, and its substrate H3S10. These findings implicate a central role for miR-93 in high glucose-induced chromatin remodelling in the kidney, and provide evidence for a previously unrecognized role for Msk2 as a target for DN therapy., Podocyte injury is central to kidney dysfunction in diabetic nephropathy. Here the authors show that Msk2 is a target of miR-93 and this interaction mediates pathogenic chromatin remodelling in diabetic nephropathy.

The increasing prevalence of multidrug-resistant Gram-negative infections has led to renewed interest in the use of systemic polymyxin B. However, the nephrotoxic properties of polymyxin B are still poorly understood. The objective of this study was to characterize nephrotoxicity associated with polymyxin B, with an emphasis on examining the impact of dosing frequencies on the onset of nephrotoxicity. Sprague-Dawley rats were divided into two groups and administered the same total daily dose of polymyxin B subcutaneously but with different dosing frequencies (either 20 mg/kg of body weight every 24 h [q24h] or 5 mg/kg q6h). Drug concentrations in renal tissue were compared between the two groups at 24 h. Kidney tissues were harvested at 48 h and compared histologically. Serum creatinine was measured daily for up to 10 days, and nephrotoxicity was defined as a significant elevation in serum creatinine (≥2× baseline). Kaplan-Meier analysis was used to compare the onset of nephrotoxicity. Polymyxin B-induced nephrotoxicity manifested as elevation in serum creatinine and acute tubular necrosis. Extensive injury of the proximal tubules was observed. The lesions were more severe and higher drug concentrations were achieved in the kidneys of the q6h dosing group. The q24h dosing group experienced a more gradual onset of nephrotoxicity, which could be attributed to the lower kidney tissue drug concentrations (48.5 ± 17.4 μg/g versus 92.1 ± 18.1 μg/g of polymyxin B1, P = 0.04). Preferential accumulation of polymyxin B in the kidneys suggests that uptake to renal cells is a nonpassive process and q24h dosing was less nephrotoxic than q6h dosing.

Retroperitoneal sarcoma is a rare tumor accounting for 10 - 15% of all soft tissue malignancies with an incidence of 2.5 per million. Of those, liposarcoma is the most common type of retroperitoneal sarcoma accounting for 41% of cases. It usually presents late with vague symptoms such as abdominal discomfort or palpable mass. Vascular invasion is seen in 18% of retroperitoneal sarcomas but acute renal failure secondary to bilateral renal artery invasion/stenosis by these tumors has never been described yet. In this report, we describe the first case, to our knowledge, in the medical literature and discuss epidemiology, diagnosis, and management. Treatment is primarily surgical and the ability to completely resect the tumor is the most important predictor of survival. Active clinical trials are currently testing the use of adjunct chemotherapy and radiotherapy to improve morbidity and mortality.

PAX2 and PAX8 are transcription factors that are essential in embryonic development of müllerian organs. They may also play a role in tumor development in these organs. The diagnostic utility of PAX2 and PAX8 relative to one another has not been comprehensively studied. Archival tissue samples for normal or non-neoplastic tissue (251), primary epithelial neoplasms (316 for PAX2 and 357 for PAX8), and metastatic epithelial neoplasms (16), all of müllerian origin, were subjected to PAX2 and PAX8 immunostaining. The staining frequency, extent, and intensity for these markers were compared. Virtually identical PAX2 and PAX8 expressions were noted in non-neoplastic tissue. They were constantly seen in most epithelial cells (but not in stromal cells) of the endocervix, endometrium, fallopian tube, paratubal cyst, endosalpingiosis, endometriosis, and endometrial polyp. Within the primary epithelial neoplasms, PAX2 and PAX8 expression was noted in 55% and 98% of serous tumors, 25% and 94% of endometrioid tumors, 19% and 100% of clear cell tumors, 11% and 67% of transitional/undifferentiated tumors, and 10% and 22% of mucinous tumors, respectively. Regardless of histologic subtypes, PAX2 staining was noted in fewer cells and with less staining intensity compared with PAX8. No tumor showed only PAX2 staining. Within the metastatic carcinomas, PAX2 and PAX8 expression was noted in 38% and 98% of cases, respectively, with a diffuse and strong staining for PAX8, contrasting with a patchy and weak PAX2 expression. PAX2 and PAX8 are constantly expressed in normal or non-neoplastic tissue of müllerian origin. For primary and metastatic müllerian epithelial tumors, PAX8 shows strong and diffuse staining in most cases of all histologic subtypes, except in mucinous tumors. In contrast, PAX2 expression is always less than PAX8, and exclusive staining for PAX2 is not seen. PAX8 supersedes PAX2 as probably the best epithelial marker hitherto for primary or metastatic müllerian epithelial tumors.

Urothelial carcinoma (UC) is the most common malignant neoplasm of the urinary tract. Metastases of UC are most common in the regional lymph nodes, lungs, liver, bone, and adrenal glands. Fine-needle aspiration cytology diagnosis of such metastases can be difficult, particularly in the setting of incomplete clinical history or when multiple primary neoplasms may be present. This review focuses on the cytologic features helpful in differentiating UC from its potential mimics, as well as ancillary studies that may be helpful in the distinction.

Benign epithelial and nonepithelial inclusions have been found in lymph nodes in multiple body sites. These inclusions have been seen in cervical, axillary, mediastinal, abdominal, and pelvic lymph nodes. They appear as benign epithelial, parathyroid, decidual, mesothelial, angiolipomatous, nevus cells, or Tamm—Horsfall protein. Although heterotopic salivary gland tissue is not infrequent in paraparotid lymph nodes, it has only been described in lymph nodes of the pulmonary hilum once. A 68-year-old woman with gastric lymphoma now in remission presented for routine follow-up and was found to have a lung mass. After a fine needle aspiration biopsy diagnosis of adenocarcinoma, lobectomy and lymph node dissection were performed. Histological sections of lung demonstrated a well-differentiated adenocarcinoma and one lymph node, which displayed a subcapsular nest of well-formed salivary glands occupying approximately one third of the nodal tissue. The inclusion was composed of acinar cells of both serous and mucinous types, but ductal type of cells were not seen. Identification of heterotopic tissue in lymph nodes is of great importance for patient management. Misdiagnosing benign glandular inclusions for metastasis could potentially lead to incorrect tumor staging. Benign salivary gland tissue inclusions should be considered in the differential diagnosis when evaluating for metastatic adenocarcinoma. The salivary gland inclusion in pulmonary hilar lymph node may be histogenetically related to the minor salivary glands, which are located within the bronchial submucosa.

Vascular lesions are encountered frequently in renal biopsy specimens of patients with systemic lupus erythematosus (SLE) and can present in a variety of morphologic forms. True renal lupus vasculitis (TRLV) is one of the rare vascular lesions associated with lupus nephritis that has been infrequently reported in the medical literature. The primary focus on glomerular pathology and collective classification of the vascular lesions under lupus vasculopathy is one of the reasons why this form of inflammatory vasculitis has been under-recognized as a separate disease entity. Here we have comprehensively reviewed the literature on renal vascular involvement in SLE for a better understanding of the epidemiology, morphologic features, pathogenesis, clinical course and treatment of TRLV. It can be morphologically differentiated from other forms of renal vascular lesions in lupus nephritis, i.e. arteriosclerosis, uncomplicated vascular immune deposits, non-inflammatory necrotizing vasculopathy, and thrombotic microangiopathy. Despite close similarities with antineutrophil cytoplasmic autoantibody associated vasculitis (AASV), there are certain morphological differences that warrant a thorough investigation of the possible pauci-immune mechanism of pathogenesis. The vasculitis follows a severe clinical course in general with rapid progression to renal failure, although favorable outcomes have been reported in certain cases. The standard use of steroids and cytotoxic drugs has yielded variable results in the treatment of TRLV. Current treatment modalities being used in lupus nephritis and AASV have been compared in this article with focus on drugs acting on the inflammatory cells implicated in TRLV pathogenesis.

PAX-2 is a transcription factor that controls the development of the kidney, organs deriving from the mesonephric (Wolffian) duct, and those related to the Müllerian duct. Although PAX-2 is shown to be a sensitive marker for tumors derived from these organs, but whether it is specific, that is, whether other tumor types also express PAX-2, has not been systematically evaluated in either primary or metastatic tumors. Tissue sections from 937 normal or reactive tissue samples, 759 primary neoplasms, and 332 metastatic neoplasms were submitted to PAX-2 immunostain. Among the non-neoplastic tissue, PAX-2 was expressed in glomerular parietal epithelial cells, renal collecting duct cells, atrophic renal tubular cells, epithelial cells of ovarian surface, fallopian tube, endocervix, endometrium, seminal vesicle, and lymphocytes. Among the primary neoplasms, PAX-2 was noted in 104/122 (85%) of renal cell carcinoma, 31/95 carcinomas of Müllerian origin, 17/17 (100%) lymphomas, 4/4 (100%) nephrogenic adenomas, and 1/16 (6%) benign parathyroid tumors, but was negative in 477 other tumors. Among the metastatic tumors, PAX-2 was noted in 70/95 (74%) metastatic renal cell carcinomas, 14/20 (70%) metastatic tumors of Müllerian origin, 1/20 (5%) metastatic colon carcinoma of lymph nodes, 1/62 (2%) metastatic breast carcinoma of lymph nodes, but was not seen in the remaining 247 metastatic tumors. PAX-2 expression in non-neoplastic mature tissue is limited to the organs whose embryonic development depends on this transcription factor. PAX-2 is a sensitive and specific marker for tumors of renal or Müllerian origin in both primary and metastatic contexts.

Cystic changes may develop in kidneys of patients with end-stage renal disease treated with long-term dialysis, a condition termed acquired cystic kidney disease. Renal neoplasms frequently develop in this process and they display a wide morphologic spectrum encompassing all of the usual renal tumors. However, one histologic type among them, characterized by tumoral deposition of calcium oxalate crystals, is seen only in the context of acquired cystic kidney disease. This communication reports one such tumor and reviews the clinicopathologic features of acquired cystic kidney disease and the renal neoplasms associated with this condition, with special emphasis on the particular renal cell carcinoma associated with tumoral calcium oxalate deposition.

Because thyrolipoma (adenolipoma of thyroid) and thyrolipomatosis (diffuse lipomatosis of thyroid) are distinctively rare conditions with only few cases reported in the literature, we are reporting 5 additional cases. All the 5 patients were adult females, with ages from 38 to 79 years, who presented with thyroid masses. Four of the patients had normal thyroid function tests and one had mild hypothyroidism. All patients received partial or total thyroidectomy. The thyroid specimens showed either circumscribed yellow-tan masses (cases 1, 2, and 3) or diffuse yellow-brown discoloration (cases 4 and 5). Histologic examination revealed abundant mature fat infiltrating the affected thyroid tissue in 3 distinct patterns: (1) fat infiltration limited to follicular adenomas (thyrolipoma); (2) fat diffusely infiltrating throughout the thyroid gland (thyrolipomatosis); or (3) fat infiltration involving both follicular adenoma and their surrounding thyroid tissue. Because of the rarity of thyroid fat-containing lesions, confusion in differential diagnosis may occasionally occur. It is important to be aware during frozen section that these lesions may present as extrathyroidal nodules, which can be radioactive on intraoperative scan for parathyroid glands. In addition, a papillary thyroid carcinoma was also identified in one case of thyrolipomatosis. All patients recovered well after surgery and there has been no recurrence of the lesions after 1 to 24 years of clinical follow-up. In summary, we are reporting 5 rare cases of thyrolipoma and thyrolipomatosis with distinct histologic patterns. Previously reported cases of thyrolipomatosis were reviewed and analyzed with the current cases.

BACKGROUND Peroxisome proliferator-activated receptor (PPAR)-alpha has been implicated in the regulation of normal and pathological cellular functions, but the effect of specific gene silencing on PPARalpha-mediated function is not fully defined. AIM This study evaluated the role of PPARalpha in hypertensive renal injury induced by nitric oxide withdrawal and high salt (4% NaCl) diet [high salt/N(omega)-nitro-L-arginine (L-NNA)]. METHODS Three PPARalpha siRNA clones, siRNA(790-811), siRNA(974-995) or siRNA(1410-1431), directed at the DNA or ligand binding domain of PPARalpha mRNA or scrambled siRNA was cloned into plasmid expression vector and was injected (10 microg intravenously) in hypertensive rats. Twenty-four-hour readings of blood pressure and heart rate were taken in conscious rats using radiotelemetry. Kidney injury was evaluated by determining N-acetyl-beta-glucosaminidase excretion, expression of kidney injury molecule-1 and histopathology. PPARalpha mRNA and protein expression were also determined. RESULTS High salt/L-NNA increased PPARalpha mRNA expression three-fold, and this was abolished in rats treated with PPARalpha siRNA(790-811), siRNA(974-995) or siRNA(1410-1431). High salt/L-NNA also increased blood pressure but reduced heart rate without affecting pulse pressure. However, blood pressure was further increased in rats treated with PPARalpha siRNA(790-811) (37 +/- 3%, P < 0.05). High salt/L-NNA also increased N-acetyl-beta-glucosaminidase excretion and expression of kidney injury molecule-1. However, PPARalpha siRNA(790-811) did not affect N-acetyl-beta-glucosaminidase excretion but reduced kidney injury molecule-1 expression. Histopathology of kidney tissues in high salt/L-NNA-treated rats revealed global, fibrinoid and tubular interstitial necrosis that was blunted by PPARalpha siRNA(790-811). CONCLUSION These data suggest that increased PPARalpha expression is a protective mechanism in hypertensive renal injury induced by nitric oxide withdrawal/high salt diet and that siRNAs targeting the DNA-binding domain of PPARalpha gene elicited differential effects on hypertension and kidney injury.

Synchronous renal and adrenal masses are uncommon. Although adrenal masses in the context of renal cell carcinoma (RCC) are often suspected as metastasis, other adrenal lesions with different therapeutic and prognostic implications may coexist with RCC. In a retrospective review of 550 radical nephrectomies with ipsilateral adrenalectomy, 80 cases of coexisting renal and adrenal masses were identified. The renal masses included 76 RCCs, 3 oncocytomas, and 1 malignant pheochromocytoma of adrenal gland involving the kidney. Although the gross pathologic impression of adrenal masses in the presence of RCC was metastasis, on histologic examination, 56% of them were found to be benign lesions (mostly adrenal adenoma/hyperplasia), whereas malignant involvement from RCC was seen in 43%. The benign and malignant nature of the adrenal lesions in the context of RCC could not be discriminated based on the size of adrenal mass. Because of the prognostic implication of direct or metastatic involvement of adrenal gland in the setting of RCC and the possibility of finding small metastatic foci, a meticulous gross and microscopic examination of adrenal glands is emphasized. Rare unusual combinations of renal and adrenal lesions such as RCC and adrenal histoplasmosis, RCC and adrenal myelolipoma, renal oncocytoma, and adrenal pheochromocytoma are also described.

Job's syndrome or autosomal dominant hyperimmunoglobulin E syndrome (Hyper-IgE) is a rare disorder that results from a STAT3 gene mutation, which results in the absence of T-helper 17 (Th17) cells and manifests as a severe immunodeficiency. Affected individuals suffer recurrent soft tissue and pulmonary infections among other manifestations, and the spectrum of the disease is still being characterized. We describe 2 sisters with Job's syndrome each with variable expressivity. However, both patients developed proteinuric kidney disease and had biopsies confirming the presence of immune complex glomerulonephritis with staining for immunoglobulins and complement components. Previous reports link Job's syndrome and the development of systemic lupus erythematosus (SLE), but proliferative immune complex glomerulonephritis has not been described. We speculate that continual internal and external antigen exposure may induce an autoimmune process similar to SLE, which in turn may account for the immune complex disease in the kidney.

The elevation of serum creatinine levels is a concern with telavancin therapy. We examined the onset of kidney injury associated with telavancin in an animal model. Urine samples were collected at baseline and daily to determine the concentrations of kidney injury molecule 1 (KIM-1), a marker for early kidney injury. When a clinically relevant exposure of telavancin was given daily to rats, some differences in kidney injury were attributed to the dosing regimen. Further investigations of alternative telavancin dosing regimens are warranted.

To study the importance of prostatic involvement by transitional cell carcinoma (TCC) in patients with bladder cancer, we examined the entire prostates by whole-mount sections from 214 radical cystoprostatectomy specimens for detailed patterns of involvement by TCC and correlated the results with lymph node metastasis and patients' survival. Prostatic involvement by TCC was detected in 69 (32%) of 214 cases. Among them, 30 (43%) patients had carcinoma in situ (CIS) and the other 39 (57%) were invasive TCC. Carcinoma in situ occurred in either prostatic urethra (n = 6, 20%) or, more commonly, in prostatic ducts/acini (n = 14, 47%), and in a combination of prostatic urethra and ducts (n = 10, 33%). Ten (26%) of the invasive TCC resulted from direct penetration from the primary tumor in the bladder, and the remaining 29 (72%) cases arose from prostatic urethra/ducts, of which 11, 13, and 5 invaded the lamina propria, prostatic stroma, and periprostatic or seminal vesical tissue, respectively. Both prostatic TCC involvement and nodal metastasis were highly significant prognostic factors for patients' survival and the survival significance of prostatic TCC involvement still existed regardless of lymph node status. Furthermore, the presence of prostatic CIS and degrees of prostatic invasion are associated with nodal metastasis and survival. Patients with prostatic CIS or urethral lamina propria invasion had a similar, but higher incidence of lymph node metastasis and lower long-term and 5-year survival than those patients without prostatic involvement. Similarly, prostatic stromal invasion and periprostatic/seminal vesical invasion had a similar, but much higher nodal metastasis and worse survival than patients with only prostatic CIS or urethral lamina propria invasion. In summary, presence of prostatic TCC involvement and levels of involvement are significant prognostic factors in patients with bladder cancer.

Renal cell neoplasms are presumably derived from different cell types of the nephron. Clear cell and papillary renal cell carcinoma (RCC) are thought to be of proximal tubular origin, whereas oncocytoma and chromophobe RCC are derived from intercalated cells of distal nephron. A few molecules, such as RCC marker and CD10, have been shown to be markers for clear cell RCC and papillary RCC. Such markers are not yet available for renal tumors presumably of the distal nephron. The expression of kidney-specific (Ksp) cadherin, a recently cloned gene thought to be transcribed exclusively in the kidney, was studied in normal human kidney, as well as in 105 primary renal neoplasms, including 42 clear cell RCC, 30 papillary RCC, 13 chromophobe RCC, and 20 oncocytomas. The expression patterns were compared with those of RCC marker. The Ksp-cadherin expression was noted preferentially in distal convoluted tubules with a basolateral membrane stain in normal kidney. All 13 chromophobe RCC and 19 of 20 oncocytomas showed diffuse and strong immunoreactivity for Ksp-cadherin, while only 14% clear cell RCC and 13% papillary RCC showed focal positivity. The RCC marker expression was detected in 85%, 98%, 15% and 0% of clear cell RCC, papillary RCC, chromophobe RCC, and oncocytoma, respectively. A few clear cell RCC and papillary RCC showed dual expression of both RCC marker and Ksp-cadherin, which appear to have distinct histologic features. These results demonstrated high sensitivity and specificity of Ksp-cadherin for distal convoluted tubules, which can be used as adjunct for diagnosis of chromophobe RCC.

Daclizumab can decrease the incidence of acute rejection (AR) in renal transplant (RTx) recipients. In this prospective study, 52 RTx patients were divided into two groups according to the dose of daclizumab: 1 mg/kg on day 0 and every 14 days for five doses (group 1, n = 30) or a truncated regimen of 2 mg/kg on day 0 and on the day of discharge (group 2, n = 22). The following variables were recorded: demographics; delayed graft function; AR at 3, 6, and 12 months; time to AR; chronic allograft nephropathy (CAN); and serum creatinine. The overall incidences of AR were 23% and 27% (P = 0.76) in groups 1 and 2, respectively, whereas at 6 months they were 21% and 18% (P = 1.0). Median time to AR was 10 days in group 1 and 94 days in group 2 (P = 0.09). The incidence of CAN was 6.6% in group 1 and 13% in group 2 (P = 0.63). These data suggest that the truncated dose of daclizumab is as effective as the standard regimen for AR prophylaxis.