Clinicopathologic and Molecular Characterization of Xanthomatous Giant Cell Renal Cell Carcinomas: Further Support for a Close Morphologic Spectrum to Eosinophilic Solid and Cystic Renal Cell Carcinomas

A recent study described a rare subtype of tuberous sclerosis complex ( TSC )-mutated renal cell carcinoma primarily characterized by Xanthomatous giant cell morphology. Only 2 cases in young individuals have been reported so far, making the correct diagnosis challenging from a pathological perspective. It remains unknown whether this tumor represents an independent subtype or belongs to other TSC -mutated tumors. We conducted a clinicopathologic evaluation and immunohistochemical profiling of 5 cases of Xanthomatous Giant Cell Renal Cell Carcinoma (XGC RCC) with confirmed TSC2 mutations through targeted DNA sequencing. In addition, we analyzed transcriptomic profiles using RNA-seq for the following samples: XGC RCC, Low-grade Oncocytic tumors (LOT), High-grade Oncocytic tumors/Eosinophilic Vacuolar Tumors (HOT/EVT), Eosinophilic Solid and Cystic Renal Cell Carcinomas (ESC RCC), Chromophobe cell Renal Cell Carcinomas (ChRCC), Renal Oncocytomas (RO), clear cell Renal Cell Carcinomas (ccRCC), and normal renal tissues. There were 2 female and 3 male patients, aged 22 to 58 years, who underwent radical nephrectomy for tumor removal. The tumor sizes ranged from 4.7 to 9.5 cm in diameter. These tumors exhibited ill-defined boundaries, showed an expansive growth pattern, and featured distinctive tumor giant cells with abundant eosinophilic to Xanthomatous cytoplasm and prominent nucleoli. All tumors had low Ki-67 proliferation indices (<1%) and demonstrated immune reactivity for CD10, PAX8, CK20, CathepsinK, and GPNMB. Next-generation sequencing confirmed TSC2 mutations in all cases. RNA sequencing-based clustering indicated a close similarity between the tumor and ESC RCC. One patient (1/5) died of an accident 63 months later, while the remaining patients (4/5) were alive without tumor recurrences or metastases at the time of analysis, with a mean follow-up duration of 43.4 months. Our research supports the concept that Xanthomatous giant cell renal cell carcinoma (XGC RCC) shares clinicopathological and molecular characteristics with ESC RCC and shows a relatively positive prognosis, providing further support for a close morphologic spectrum between the two. We propose considering XGC RCC as a distinct subtype of ESC RCC.

L1 Cell Adhesion Molecule (L1CAM) Expression and Molecular Alterations Distinguish Low-Grade Oncocytic Tumor From Eosinophilic Chromophobe Renal Cell Carcinoma

Renal low-grade oncocytic tumor (LOT) is a recently recognized renal cell neoplasm designated within the "other oncocytic tumors" category in the 2022 World Health Organization classification system. Although the clinicopathologic, immunohistochemical, and molecular features reported for LOT have been largely consistent, the data are relatively limited. The morphologic overlap between LOT and other low-grade oncocytic neoplasms, particularly eosinophilic chromophobe renal cell carcinoma (E-chRCC), remains a controversial area in renal tumor classification. To address this uncertainty, we characterized and compared large cohorts of LOT (n = 67) and E-chRCC (n = 69) and revealed notable differences between the 2 entities. Clinically, LOT predominantly affected women, whereas E-chRCC showed a male predilection. Histologically, although almost all LOTs were dominated by a small-nested pattern, E-chRCC mainly showed solid and tubular architectures. Molecular analysis revealed that 87% of LOT cases harbored mutations in the tuberous sclerosis complex (TSC)-mTOR complex 1 (mTORC1) pathway, most frequently in MTOR and RHEB genes; a subset of LOT cases had chromosomal 7 and 19q gains. In contrast, E-chRCC lacked mTORC1 mutations, and 60% of cases displayed chromosomal losses characteristic of chRCC. We also explored the cell of origin for LOT and identified L1 cell adhesion molecule (L1CAM), a collecting duct and connecting tubule principal cell marker, as a highly sensitive and specific ancillary test for differentiating LOT from E-chRCC. This distinctive L1CAM immunohistochemical labeling suggests the principal cells as the cell of origin for LOT, unlike the intercalated cell origin of E-chRCC and oncocytoma. The ultrastructural analysis of LOT showed normal-appearing mitochondria and intracytoplasmic lumina with microvilli, different from what has been described for chRCC. Our study further supports LOT as a unique entity with a benign clinical course. Based on the likely cell of origin and its clinicopathologic characteristics, we propose that changing the nomenclature of LOT to "Oncocytic Principal Cell Adenoma of the Kidney" may be a better way to define and describe this entity.

Immunohistochemical expression of cytochrome P4A11 (CYP4A11), carbonic anhydrase 9 (CAIX) and Ki67 in renal cell carcinoma; diagnostic relevance and relations to clinicopathological parameters

BACKGROUND

Cytochrome P4A11 (CYP4A11) is a member of cytochrome p450 family, which is involved in arachidonic acid metabolism that participates in promoting malignant cell proliferation, progression, and angiogenetic capacity. Carbonic Anhydrase 9 (CAIX) is a transmembrane protein that plays an integral part in regulating hypoxia which affects cancer cell metabolism, proliferation and promotes metastasis. The aim of this study was to evaluate the immunohistochemical expression of CYP4A11, CAIX and ki67 in RCC subtypes in relation to clinicopathological parameters and to evaluate the diagnostic significance of CYP4A11 and CAIX in differentiating renal cell carcinoma (RCC) subtypes.

MATERIALS AND METHODS

one hundred primary RCC cases, collected from Pathology Department, Faculty of Medicine, Tanta University and from private laboratories, were evaluated for immunohistochemical expression of CYP4A11, CAIX and ki67.

RESULTS

CYP4A11 was expressed in 59% of RCC; with 91.7% sensitivity and 90% specificity in differentiating clear cell and non-clear cell subtypes. CAIX was expressed in 50% of RCC; with 95% sensitivity, 80% specificity. High expression of CYP4A11 was statistically positively associated with higher tumor grade, high expression of CAIX was statistically positively associated with lower tumor grade and absence of necrosis and high ki67 labeling index was significantly associated with clear cell subtype, larger tumor sizes, higher tumor grade, advanced tumor stage, fat invasion and vascular invasion.

CONCLUSIONS

CYP4A11 and CAIX can be used as diagnostic markers to differentiate clear cell RCC from other subtypes. CYP4A11 is more diagnostically accurate and specific than CAIX. High expression of CYP4A11, low CAIX expression and high ki67 labeling index were related to features of aggressive tumor behavior.

Reclassifying Papillary, Oncocytic and Chromophobe Renal Tumours Based on the 5 < sup > th < /sup > Who Classification 2022

OBJECTIVE

The classification of renal tumors is expanding with the addition of new molecular entities in the 5th World Health Organization classification. Apart from this, the major updates in the definition of papillary renal cell carcinoma are that these tumors are no longer subtyped into type 1 and type 2. In oncocytic tumors, the new molecularly defined renal tumors, emerging and novel entities need to be considered in the diagnosis of oncocytic and chromophobe renal tumors.

MATERIAL AND METHODS

This is a retrospective study to review and reclassify papillary, oncocytic, and chromophobe renal tumors based on the new WHO classification and correlate with clinical data, gross, microscopic features, and immunohistochemistry markers.

RESULTS

A total of thirteen cases were reviewed and the tumor grade was changed for three out of four cases of papillary renal cell carcinoma and a single case was recategorized and graded. In nine cases of oncocytic and chromophobe renal tumors, the diagnoses were modified in 3 cases.

CONCLUSION

Newly defined molecular renal tumors require advanced immunohistochemistry markers and molecular tests. This poses diagnostic challenges to pathologists practicing in low resource settings where molecular tests are not available.

Identification of adhesion-associated extracellular matrix component thrombospondin 3 as a prognostic signature for clear cell renal cell carcinoma

PURPOSE

Clear cell renal cell carcinoma (ccRCC) is a highly aggressive disease, and approximately 30% of patients are diagnosed at the metastatic stage. Even with targeted therapies, the prognosis of advanced ccRCC is poor. The aim of this study was to investigate clinical prognosis signatures by analyzing the ccRCC datasets in The Cancer Genome Atlas (TCGA) and the Clinical Proteomic Tumor Analysis Consortium (CPTAC) and the function of thrombospondin 3 (THBS3) in ccRCC.

MATERIALS AND METHODS

We analyzed the ccRCC datasets in TCGA and CPTAC to search for extracellular matrix (ECM)-related and adhesion-associated genes, and conducted overall survival, Cox, and receiver operating characteristic analyses. We also performed CCK8, colony formation, and transwell assays to compared the proliferation and migration ability of THBS3 knockout cells with those of cells without THBS3 knockout.

RESULTS

Comprehensive bioinformatics analysis revealed that THBS3 is a novel candidate oncogene that is overexpressed in ccRCC tumor tissue and that its elevated expression indicates poor prognosis. Our study also showed that knockdown of THBS3 inhibits proliferation, colony formation, and migration of ccRCC cells.

CONCLUSIONS

In summary, our data have revealed that THBS3 is upregulated in cancer tissues and could be used as a novel prognostic marker for ccRCC. Our findings thus offer theoretical support with bioinformatics analyses to the study of ECM and adhesion proteins in ccRCC, which may provide a new perspective for the clinical management of ccRCC.

Differential Immunohistochemical and Molecular Profiling of Conventional and Aggressive Components of Chromophobe Renal Cell Carcinoma: Pitfalls for Diagnosis

Chromophobe renal cell carcinoma (ChRCC) is a relatively rare subtype of RCC with a characteristic histologic appearance. Most ChRCC are slow growing, but sarcomatoid differentiation and metastases can occur, indicative of aggressive behavior and poor prognosis. Herein, we characterize ten ChRCC with aggressive components, defined as sarcomatoid change and/or metastasis. Immunohistochemistry and next-generation sequencing was performed on available formalin-fixed paraffin-embedded tissue, with differential profiling of conventional and aggressive components. All ten cases showed a conventional component of renal tumor morphologically consistent with ChRCC: three had sarcomatoid change, four had metastases, and three had both sarcomatoid change and metastases. In the primary conventional components, a typical ChRCC IHC pattern (CK7+, CD117+ and CAIX-) was observed in 8/10 cases; 2 cases had rare CK7 staining. In the aggressive components, CD117 and/or CK7 was lost in 7/10 cases; 3 cases showed loss of both. Two of 10 cases showed significant CAIX staining in the aggressive component. All 7 cases that had molecular profiling performed showed characteristic chromosomal losses reported for ChRCC, though two cases showed additional complex copy number alterations in the aggressive component only. Recurrent TP53 mutations (TP53m) were also seen; however surprisingly, the conventional and aggressive components had no shared TP53m: a TP53m was private to aggressive components in 2 cases; to the conventional component in 1 case; and in 4 cases, components demonstrated different TP53m. Of the 21 pathogenic alterations identified in 7 tumors, only a PTEN splicing alteration was shared between both components in one case. In conclusion, ChRCC can have IHC staining patterns and molecular profile that differ between conventional and aggressive components. Interpretation of stains on metastases or small biopsies to determine histologic subtype can be misleading. The lack of shared pathogenic mutations between the two components supports a model in which aggressive ChRCC can have convergent subclones with different TP53m.

Prognostic role of macrophage migration inhibitory factor in patients with clear cell renal cell carcinoma

Macrophage migration inhibitory factor (MIF) is a cytokine that mediates the interaction between malignant cells and the innate immune system. Recently, MIF has received attention for its role in tumorigenesis. We evaluated the prognostic role of MIF in clear cell renal cell carcinoma (CCRCC).A total of 152 patients, who underwent nephrectomy for CCRCC were enrolled in this study. Immunohistochemical staining of tissue microarray blocks containing 298 cores-2 cores per CCRCC patient was performed. The relationship between MIF expression and clinicopathological factors was evaluated. Total RNA and protein were extracted from 7 RCC (renal cell carcinoma) cell lines. MIF was knocked down in Caki-2 cells, and a wound healing assay was performed to evaluate migratory activity.Among the 298 cores, 180 (60.4%) were positive for MIF. Multivariate analysis, showed that, CCRCC patients with negative MIF expression exhibited poor disease-free survival (hazard ratio: 2.087, 95% confidence interval: 0.821-5.307, P value: .023) and poor disease-specific survival (hazard ratio: 2.101, 95% confidence interval: 1.009-4.374, P value: .047). The wound healing assay revealed that cell confluence was lower in MIF-deficient Caki-2 cells than in control cells.Negative MIF expression might be an independent prognostic marker for patients with CCRCC.

HNF-1β as an immunohistochemical marker for distinguishing chromophobe renal cell carcinoma and hybrid oncocytic tumors from renal oncocytoma

The histologic features of renal oncocytoma (RO) are similar to those for the more aggressive chromophobe renal cell carcinoma (ChRCC). To assess immunohistochemical markers of the two, the sensitivity and specificity of cytokeratin 7 (CK7) and C-kit, as well as hepatocyte nuclear factor-1β (HNF-1β), were analyzed. Typical cases of ChRCC and RO at Severance Hospital between July 2014 and July 2018 were selected retrospectively. Among 44 cases, 17 were unanimously compatible with ChRCC, 16 were RO, and 11 cases were indeterminate. Samples from all selected cases were used for immunostaining with antibodies against CK7, C-kit, HNF-1β, and CD10. Immunostaining demonstrated complete loss of HNF-1β expression in 11 out of 17 (64.7%) ChRCC cases and a partial, but significant loss in > 50% of tumor cells in the remaining 6 cases (35.3%). In contrast, HNF-1β expression was preserved in tumor cells of RO cases. Fourteen of 17 ChRCC cases (82.4%) were diffusely positive for CK7, whereas cases of RO were focal positive or negative. C-kit staining did not show a significant difference between ChRCC and RO. Two of five ChRCC cases showing diffuse immunoreactivity for CD10 had poor prognoses of local invasion, distant metastasis, or death. Loss of HNF-1β expression is a useful marker with which to diagnose ChRCC, especially in cases with confusing histologic findings or equivocal CK7 staining. Additionally, CD10 staining in high-grade ChRCC aids in diagnosis and prediction of the clinical prognosis.

Antigen Retrieval and Its Effect on the MALDI-MSI of Lipids in Formalin-Fixed Paraffin-Embedded Tissue

Formalin-fixed paraffin-embedded (FFPE) tissue represents the primary source of clinical tissue and is routinely used in MALDI-MSI studies. However, it is not particularly suitable for lipidomics imaging given that many species are depleted during tissue processing. Irrespective, a number of solvent-resistant lipids remain, but their extraction may be hindered by the cross-link between proteins. Therefore, an antigen retrieval step could enable the extraction of a greater number of lipids and may provide information that is complementary to that which can be obtained from other biomolecules, such as proteins. In this short communication, we aim to address the effect of performing antigen retrieval prior to MALDI-MSI of lipids in FFPE tissue. As a result, an increased number of lipid signals could be detected and may have derived from lipid species that are known to be implicated in the lipid-protein cross-linking that is formed as a result of formalin fixation. Human renal cancer tissue was used as a proof of concept to determine whether using these detected lipid signals were also able to highlight the histopathological regions that were present. These preliminary findings may highlight the potential to enhance the clinical relevance of the lipidomic information obtained from FFPE tissue.

High level of EZH2 expression is linked to high density of CD8-positive T-lymphocytes and an aggressive phenotype in renal cell carcinoma

Purpose

Enhancer of zeste homolog 2 (EZH2), the catalytic part of the Polycomb repressive complex 2 (PRC2), has a prognostic role in renal cell carcinoma (RCC) and was recently shown to modulate the immune response by reducing tumor cell immunogenicity.

Methods

To investigate whether the prognostic role of EZH2 might be driven by a modified immune environment, more than 1800 RCCs were analyzed in a tissue microarray for EZH2 expression and CD8 positive lymphocytes were quantitated by automated digital imaging.

Results

EZH2 positivity was found in 75.2% of 1603 interpretable tumors. In clear cell RCC, high EZH2 expression was significantly linked to high ISUP, Furmann, and Thoenes grade (p < 0.0001 each), advanced stage (p < 0.0001), nodal (p = 0.0190) and distant metastasis (p < 0.0001) as well as shortened overall (p < 0.0027) and recurrence free survival (p < 0.0001). The density of CD8+ cells varied from 0 to 5048 cells/mm² (Median 120 cells/mm²). A high CD8+ count was significantly associated with high ISUP, Fuhrmann, and Thoenes grade (p < 0.0001 each), advanced tumor stage (p = 0.0041), distant metastasis (p = 0.0026) as well as reduced overall survival (p = 0.0373) and recurrence free survival (p = 0.0450). The density of CD8+ cells continuously increased with raising EZH2 levels (p < 0.0001).

Conclusion

Our data support a striking prognostic role of both EZH2 expression and the density of CD8+ cells in RCC. The tight relationship of EZH2 expression and CD8+ cell counts in RCC is consistent with models suggesting that EZH2 overexpression can be caused by high lymphocyte content in certain tumor types. Such a mechanism could explain the unique finding of high lymphocyte counts driving poor prognosis in RCC patients.

Defining the human kidney N-glycome in normal and cancer tissues using MALDI imaging mass spectrometry

Clear-cell renal cell carcinoma (ccRCC) presents challenges to clinical management because of late-stage detection, treatment resistance, and frequent disease recurrence. Metabolically, ccRCC has a well-described Warburg effect utilization of glucose, but how this affects complex carbohydrate synthesis and alterations to protein and cell surface glycosylation is poorly defined. Using an imaging mass spectrometry approach, N-glycosylation patterns and compositional differences were assessed between tumor and nontumor regions of formalin-fixed clinical ccRCC specimens and tissue microarrays. Regions of normal kidney tissue samples were also evaluated for N-linked glycan-based distinctions between cortex, medullar, glomeruli, and proximal tubule features. Most notable was the proximal tubule localized detection of abundant multiantennary N-glycans with bisecting N-acetylglucosamine and multziple fucose residues. These glycans are absent in ccRCC tissues, while multiple tumor-specific N-glycans were detected with tri- and tetra-antennary structures and varying levels of fucosylation and sialylation. A polycystic kidney disease tissue was also characterized for N-glycan composition, with specific nonfucosylated glycans detected in the cyst fluid regions. Complementary to the imaging mass spectrometry analyses was an assessment of transcriptomic gene array data focused on the fucosyltransferase gene family and other glycosyltransferase genes. The transcript levels of the FUT3 and FUT6 genes responsible for the enzymes that add fucose to N-glycan antennae were significantly decreased in all ccRCC tissues relative to matching nontumor tissues. These striking differences in glycosylation associated with ccRCC could lead to new mechanistic insight into the glycobiology underpinning kidney malignancies and suggest the potential for new therapeutic interventions and diagnostic markers.

Analyses of biomarkers of exposure to nephrotoxic mycotoxins in a cohort of patients with renal tumours

The Czech Republic occupies the first place in the world in the frequency of renal and other urinary tract tumours, but their aetiology is unknown. To explore whether carcinogenic and nephrotoxic mycotoxins may contribute to kidney diseases in the Czech population, biomarkers of ochratoxin A (OTA) and citrinin (CIT) exposure were determined in biological specimens from a cohort of 50 patients with malignant renal tumours. Biomarker analyses in blood and urine samples used validated targeted methods for measuring OTA and CIT plus dihydrocitrinone (DH-CIT) after enrichment of analytes by specific immunoaffinity clean-up. OTA and CIT plus its metabolite DH-CIT were frequently detected in patient urine samples (OTA 62%; CIT 91%; DH-CIT 100%). The concentration ranges in urine were 1-27.8 ng/L for OTA, 2-87 ng/L for CIT and 2-160 ng/L for DH-CIT. The analyses of blood samples revealed also a frequent co-occurrence of OTA and CIT, in the ranges of 40-870 ng/L serum for OTA and 21-182 ng/L plasma for CIT. This first analysis of biomarkers in blood and urine samples of Czech patients revealed no major differences in comparison with published data for the general healthy Czech and European populations. Nonetheless, a frequent co-occurrence of CIT and OTA biomarkers in patient samples may be of interest with regard to potential interactions with other risk factors for renal disease.

Immunohistochemical negative expression of ezrin predicts poor prognosis in clear cell renal cell carcinoma

PURPOSE

To analyze the immunohistochemical expression of ezrin and moesin in clear cell renal cell carcinoma (ccRCC). These proteins, as part of the ezrin-radixin-moesin complex link the cell membrane to the actin cytoskeleton, affecting such processes as cell adhesion, cell survival, cell motility, and signal transduction. Our aim was to examine the impact of their expression on clinical outcomes and survival rates.

PATIENTS AND METHODS

Five hundred seventy-five consecutive patients who had been treated surgically for ccRCC in a single center between 1985 and 2016 were selected. A single pathologist reviewed all cases to perform a uniform reclassification and determined the most representative tumor areas for construction of a tissue microarray.

RESULTS

Of all ccRCC specimens, 106 (18.3%) were negative for ezrin, and 469 (81.7%) had positive ezrin expression; 16 (2.8%) were negative and 559 (97.2%) were positive for moesin, respectively. Ezrin expression was associated with pT stage (P < 0.001), clinical stage (P = 0.012), synchronic metastasis (P < 0.001), incidental tumors (P = 0.007), and International Society of Urological Pathology histological grade (P = 0.025). There was a correlation between moesin expression and clinical stage (P = 0.027), pT stage (P = 0.025), and pN stage (P = 0.007). Ezrin expression significantly influenced tumor-related deaths. By multivariate analysis, negative ezrin expression was an independent risk factor for disease-specific survival (HR 1.89; 95% CI 1.11-3.20).

CONCLUSIONS

Negativity for ezrin in ccRCC patients significantly impacts survival rates. We encourage further prospective studies to analyze ezrin analysis to evaluate its significance in the prognosis of ccRCC.

Chemoenzymatic synthesis of the oligosaccharide moiety of the tumor-associated antigen disialosyl globopentaosylceramide

Disialosyl globopentaosylceramide (DSGb5) is often expressed by renal cell carcinomas. To investigate properties of DSGb5, we have prepared its oligosaccharide moiety by chemically synthesizing Gb5 which was enzymatically sialylated using the mammalian sialyltransferases ST3Gal1 and ST6GalNAc5. Glycan microarray binding studies indicate that Siglec-7 does not recognize DSGb5, and preferentially binds Neu5Acα(2,8)Neu5Ac containing glycans.

[Clinical challenges and implications of intratumor heterogeneity]

Tumors display a high, albeit variable, grade of intratumor heterogeneity, both from a clinical and a morphological viewpoint. Furthermore, recent methods of large-scale molecular analysis demonstrate to what extent tumors can also be heterogeneous from a molecular perspective. This is of paramount importance for patients as it has a great impact on the success of so-called precision therapies and explains the reason for a significant number of therapeutic failures in modern oncology. We present an up-to-date review of the latest findings in a group of tumors with a high social impact, commonly seen in the daily routine of the pathology laboratory.

The Prognostic Role of the Non-Canonical Nuclear Factor-Kappa B Pathway in Renal Cell Carcinoma Patients

BACKGROUND

In the United Kingdom, 8,000 cases of renal cancer are diagnosed each year, with a 5-year survival rate of 50%. Treatment options are limited; a potential therapeutic target is the non-canonical nuclear factor-kappa B (NF-κB) pathway. This pathway plays a role in multiple oncogenic processes in solid tumors. The aim of this study was to investigate the non-canonical nuclear factor pathway in renal cell carcinoma (RCC).

MATERIALS AND METHODS

NIK, IKKα, and RelB were investigated via immunohistochemistry in a cohort of 192 patients with clear cell renal cancer.

RESULTS

High cytoplasmic NIK was associated with poorer cancer-specific survival (p = 0.006) and 10-year survival stratified from 85% (low) to 65% (high, p = 0.005). Similarly, high cytoplasmic RelB was associated with poorer cancer-specific survival (p = 0.041) and 10-year survival stratified from 88% (low) to 73% (high, p = 0.030). When clinicopathological characteristics were assessed, cytoplasmic NIK was associated with survival (p = 0.014), whereas cytoplasmic RelB was associated with increased tumor grade (p = 0.020) and decreased inflammation (p = 0.019). Upon multivariate analysis, it was found that cytoplasmic NIK was independently associated with cancer-specific survival (p = 0.009).

CONCLUSIONS

The non-canonical NF-κB pathway is associated with poorer cancer-specific survival in RCC patients, making it a viable target for therapeutic intervention. Furthermore, cytoplasmic NIK is a potential prognostic biomarker for this disease.

Immunohistochemical characteristics of renomedullary interstitial cell tumor: a study of 41 tumors with emphasis on differential diagnosis of mesenchymal neoplasms

Renomedullary interstitial cell tumors (RMICTs) are almost always incidentally identified either at autopsy or upon resection of the kidney for other reasons. However, rare cases that are large, resulting in a clinical mass, have been reported. The immunohistochemical phenotype of usual, incidental RMICT using modern soft tissue tumor markers is largely unknown, however, providing little information to aid in classification of larger or atypical tumors. We retrieved 41 RMICTs from 36 patients and studied pathologic characteristics including morphology, immunohistochemistry (S100, keratin AE1/AE3, smooth muscle actin, desmin, estrogen and progesterone receptors, calponin, CD34, CD35), and histochemical staining. Data collected included age, sex, tumor size, laterality, and indication for kidney examination. RMICTs (n = 41) were identified in 23 men and 13 women, with a mean age of 57 years (range, 24-83 years); tumor sizes ranged from less than 1 to 13 mm (median, 4 mm). Kidneys were resected for 32 tumors, 1 chronic pyelonephritis, 1 trauma, and 2 autopsies. All (41; 100%) had entrapped renal tubules, 5 (12%) of which included cystic or dilated tubules. Most (35; 85%) had collagenous fibers, all of which were negative for Congo red. RMICT demonstrates a largely negative immunohistochemical phenotype with weak-to-moderate labeling for smooth muscle actin and calponin that is substantially less than myofibroblastic lesions. Positive staining for estrogen and progesterone receptors is common (61%), which could overlap with mixed epithelial and stromal tumor and other entities; however, staining is typically weak. CD34 is usually negative, with occasional weak labeling, in contrast to solitary fibrous tumor.

Immunohistochemistry of Complement Response on Human Renal Cell Carcinoma Biopsies

The goal of the study was to characterize the complement humoral and cellular antitumor responses on primary renal cell carcinoma biopsies. As an original observation, complement activation was found on 11/22 cases. Classical complement pathway activation was characterized by tumor C1q complement protein and IgG deposition (5/22 cases). Alternative or nonimmune complement pathway activation was seen as tissue deposition of C3 (6/22 cases). The membrane attack complex was present in cases with alternative complement pathway activation at the sites of tumor necrosis. Renal cell carcinomas with complement activation overexpressed at least one of the complement regulatory factors (membrane cofactor protein, decay accelerating factor, membrane attack complex inhibitor) and major histocompatibility complex class II molecules. Tumor infiltrating lymphocytes were present in most of the renal cell carcinomas with complement activation (8/11). However, the number of tumor-infiltrating lymphocytes was correlated with the intensity of major histocompatibility complex-ll expression in 18/22 cases. Detection of complement activation and immune cell infiltrates on renal cell carcinoma primary biopsies may serve as a new predictive factor for immunotherapy.

Cadherins and Integrins in Renal Cell Carcinoma an Immunohistochemical Study

Aims and Background

The aim of this study was to determine the expression of cadherins and integrins in renal cell carcinoma (RCC) and their relationship with tumor morphology and TNM status.

Methods

Cadherin and integrin expression was investigated using an indirect immunoperoxidase technique, applying antibodies to E-, N-, P- and VE-cadherin and to α1, α2, α3, α4, α5, α6 and αv integrin subunits. Correlation of semiquantitatively scored adhesion molecule levels with histopathological parameters (cytology, growth pattern, nuclear grade) and TNM status was performed for 24 RCCs (17 clear cell, 3 granular, 3 spindle cell and 1 chromophobe cell type according to the WHO classification).

Results

E-cadherin and N-cadherin were present in most cases (88% and 67%, respectively) and were usually coex-pressed. T3 RCCs displayed higher E-cadherin and N-cadherin levels than T1/T2 tumors regardless of tumor grade, suggesting that impairment of their function might exist without actual loss from tumor cells. P-cadherin was found focally in two RCCs only, while VE-cadherin was present on stromal vessel endothelium in five tumors, showing no differences with regard to cell type, growth pattern, tumor grade or TNM status. All integrins were present in the studied RCCs (ranging from 12% for α5 to 79% for α3), including those that are normally absent from adult kidney tissue (α4 and α5). Tumors of higher grade showed increased αv and decreased α6 levels, while RCCs with metastases less often showed diffuse α3 presence and never expressed α5 integrin.

Conclusions

Our results suggest that the level of expression of N-cadherin and some integrins (most notably α3, α6, and α5) is associated with the capacity of RCC for local and distant spread, regardless of tumor grade.

HMB45 and Melan-A Expression in Renal Angiomyolipoma and Their Significance for the Diagnosis

Aims and Background

The melanosome-associated proteins, also called HMB45 and melan-A, are also present in renal angiomyolipoma. The aim of the present study was to evaluate the expression of HMB45 and melan-A in mesenchymal cells of renal angiomyolipoma and to investigate their significance in the differential diagnosis.

Methods

Twelve patients, 9 females and 3 males diagnosed with renal angiomyolipomas, were included in the present study. The most representative tumor tissue block was chosen from each case, and 5-üm sections were taken to poly-l-lysin-coated slides for immunohistochemical staining. The standard streptavidin-biotin immunoperoxidase method was used for immunostaining with HMB45 and melan-A antibodies.

Results

All of the cases showed positive cytoplasmic immunostaining for HMB45 and melan-A. Melan-A expression was shown in smooth muscle component, adipose tissue and predominantly in the perivascular cells, whereas HMB45 immunoreactivity was stronger than melan-A expression in all cases.

Conclusions

It was concluded that HMB45 and melan-A reactivity is a useful tool to distinguish renal angiomyolipomas from other primary and secondary mesenchymal and primary epithelial tumors. Melan-A and HMB45 share similar specificities for renal angiomyolipoma. In addition, such expression in renal angiomyolipomas may occur without any evidence of nevomelanocytic differentiation. Further research is required to determine the histogenesis of this entity.

Expression of the Tumor-Associated Glycoproteins Mca, Ca 125 and Bw 495/36-P in Epithelial Tumors of the Kidney and the Urinary Bladder

The differential expression of the tumor-associated glycoproteins MCA, CA 125 and BW 495/36-P was investigated in 11 renal cell carcinomas and 11 urinary bladder carcinomas and compared with their expression in non-neoplastic tissue preparations from the kidney (n = 9) and urinary bladder (n = 12). The glycoproteins were demonstrated immunohistologically in frozen sections and additionally, in some cases, in paraffin sections. MCA and BW 495/36-P positive cells were present in all preparations except for a grade I transitional cell carcinoma of the bladder, in which no MCA-expression could be detected. In the non-neoplastic renal tissue mainly the cells of the distal tubuli were stained by the antibodies against these two glycoproteins. Carcinoma cells of the kidney and of the urinary bladder showed an increased expression of both epitopes.

CA 125, in comparison, was strongly expressed in 3 of the 11 urinary bladder carcinomas investigated but could only be shown in a few cells of a single renal cell carcinoma. Normal renal tissue showed no and the urinary bladder only very isolated CA 125 positive epithelial cells. Apart from this distribution, strong staining of the connective tissue fibers with CA 125 antibody was seen in all paraffin sections, but not in the frozen sections. This leads to the supposition that in these structures there is a CA 125 cryptantigen. The consistent expression of MCA as well as the virtual lack of CA 125 in the renal cell carcinomas are in contrast with our previous serological results, in which patients with metastatic renal cell carcinomas showed increased CA 125 in approx. 50% of cases whereas only approx. 20% had increased MCA serum levels.

[TFEB-amplified renal cell carcinoma. A case report and review of the literature]

Renal carcinomas associated with translocation of transcription factors of the MiT/TFE family include, according to the latest World Health Organization classification, carcinomas with Xp11 translocation that involve the TFE3 gene and those with translocation t(6;11)(p21;q12) that affect the TFEB gene. Each one of these sub-types have well-defined clinicopathological and molecular characteristics. Currently, progress in molecular techniques has led to the description of neoplasms with molecular changes in these same genes but with alterations different to translocation. Thus, recently, cases have been published of TFEB-amplified renal carcinomas with prognoses that vary from cases associated with translocation and could therefore represent a new entity. We present a case of TFEB-amplified renal carcinoma with a full description of the clinicopathological characteristics and an updated revision of these neoplasms.

Characterization of Seven Kidney Tumors by Flow Cytometry: Analysis of Cell Cycle, DNA Content and P-Glycoprotein Expression

Seven kidney tumors obtained from patients aged from 5 to 76 years were analyzed by flow cytometry for cell cycle, DNA content and P-glycoprotein expression involved in multidrug resistance. The DNA index seems to be an important criterion since all the tumors were aneuploid. In a case of clear cell carcinoma, two aneuploid clones were identified. In 5 cases of kidney tumors a high proportion of cells in proliferation (S + (G2 + M)) was observed; it was comprised between 13 and 33%. As for P-glycoprotein it was detected only in few tumor cells (5-15%) respectively in a case of clear cell carcinoma and in a case of Wilms' tumor.

Cadmium, lead and mercury concentrations in pathologically altered human kidneys

Heavy metals, including cadmium (Cd), lead (Pb) and mercury (Hg) act as nephrotoxic agents, particularly in the renal cortex. The aim of the study was to determine the concentrations of Cd, Pb and Hg in kidneys removed from patients due to lesions of various etiologies and from patients after the rejection of transplanted kidneys. Additionally, we determined the influence of selected biological and environmental factors on the concentrations of toxic metals. The study material consisted of kidneys with tumor lesions (n = 27), without tumors (n = 7) and its extracted grafts (n = 10) obtained from patients belongs to the north-western areas of Poland. The determined metal concentrations in the renal cortex and medulla may be arranged in the following descending order: Cd > Pb > Hg. The highest concentrations of Cd and Hg were found in the cortex, while the maximum content Pb was observed in the medulla. Significant correlations were found in the concentrations of the same metals between cortex and medulla and between Pb and Hg in the renal medulla. Pb content was higher in the renal medulla of men than in the cortex of the elderly (above 60 years of age). The highest concentrations of Pb and Hg were found in the cortex and medulla, of the kidneys had not neoplastic changes, and lower content of these metals were found in the extracted kidney grafts. In summary, renal grafts accumulate less heavy metals than cancerous kidneys, what could have been caused by immunosuppressors taken by the graft recipients. Moreover, sex, age and smoking are key factors responsible for xenobiotics concentrations.

MALDI Orbitrap Mass Spectrometry Profiling of Dysregulated Sulfoglycosphingolipids in Renal Cell Carcinoma Tissues

Matrix-assisted laser desorption/ionization coupled with Orbitrap mass spectrometry (MALDI-Orbitrap-MS) is used for the clinical study of patients with renal cell carcinoma (RCC), as the most common type of kidney cancer. Significant changes in sulfoglycosphingolipid abundances between tumor and autologous normal kidney tissues are observed. First, sulfoglycosphingolipid species in studied RCC samples are identified using high mass accuracy full scan and tandem mass spectra. Subsequently, optimization, method validation, and statistical evaluation of MALDI-MS data for 158 tissues of 80 patients are discussed. More than 120 sulfoglycosphingolipids containing one to five hexosyl units are identified in human RCC samples based on the systematic study of their fragmentation behavior. Many of them are recorded here for the first time. Multivariate data analysis (MDA) methods, i.e., unsupervised principal component analysis (PCA) and supervised orthogonal partial least square discriminant analysis (OPLS-DA), are used for the visualization of differences between normal and tumor samples to reveal the most up- and downregulated lipids in tumor tissues. Obtained results are closely correlated with MALDI mass spectrometry imaging (MSI) and histologic staining. Important steps of the present MALDI-Orbitrap-MS approach are also discussed, such as the selection of best matrix, correct normalization, validation for semiquantitative study, and problems with possible isobaric interferences on closed masses in full scan mass spectra. Graphical Abstract ᅟ.

Metanephric stromal tumor with a rare incidence of squamous epithelium: A case report and a brief review of the literature

Metanephric stromal tumor (MST) of the kidney, a rare benign pediatric neoplasm recognized for less than 20 years, is not widely known. The authors describe a case of MST with rare squamous epithelium in a 14-month-old female. A renal mass was discovered during her fetal period. After her birth, computerized tomography revealed that the mass was localized in the inferior pole of her left kidney. She then underwent nephrectomy. The tumor was an unencapsulated but well-defined mass with a white, solid and firm cut surface and had dimensions of 4cm×3.5cm×3cm. The tumor was initially diagnosed as Wilms tumor because its frozen section exhibited spindle cells with cartilaginous and rare squamous epithelial elements. However, the paraffin-embedded section of the tumor exhibited bland stromal cells surrounding the entrapped tubules; this arrangement produced an "onion-skin" appearance. The rare squamous epithelial element appeared to originate from normal renal tubules. Immunohistochemistry results were positive for CD34 and INI1, as well as a low Ki-67 expression level, but were negative for S-100, Desmin, Actin, CD117 and Catenin-β. Fluorescence in situ hybridization analysis did not detect an ETV6 rearrangement. Morphological characteristics, immunophenotyping and molecular genetic analysis indicated MST. No recurrence or metastases occurred during the follow-up period of 36 months. Epithelial elements should be examined carefully in pediatric patients with renal masses. MST should be included in their differential diagnoses.

Clinical value of pathologic examination of non-neoplastic kidney in patients with upper urinary tract malignancies

BACKGROUND/AIMS

While surgical resection remains the standard of care in the treatment of upper urinary tract malignancies, nephrectomy is a risk factor for the development of chronic kidney disease (CKD). The aim of this study was to determine whether histologic evaluation of non-neoplastic kidney could enable early identification of unrecognized kidney disease and could be of prognostic value in predicting postoperative renal outcomes.

METHODS

We retrospectively analyzed 51 patients with upper urinary tract malignancies who received uninephrectomy or uninephroureterectomy. A thorough pathologic evaluation of non-neoplastic kidney including special stains, immunofluorescence, and electron microscopic studies was performed. The degree of parenchymal changes was graded from 0 to 15.

RESULTS

Of 51 patients, only 13 showed normal kidney pathology. Fifteen patients showed glomerular abnormalities, 14 showed diabetic nephropathy, and 11 showed vascular nephropathy. There was one case each of reflux nephropathy and chronic pyelonephritis. The median histologic score was 5 points. Only 25.4% of patients had ≤ 3 points. Score more than 5 was observed in 47.1% of patients. Postoperative estimated glomerular filtration rate (eGFR) at 3 to 36 months were obtained from 90.2% of patients, and of those, 34.8% had de novo CKD. Since no one had CKD in partial nephrectomized patients, we determined risk factors for CKD in radical nephrectomized patients. Cox regression analysis revealed that postoperative AKI, preoperative eGFR, and histologic score of non-neoplastic kidney were the independent predictors for CKD.

CONCLUSIONS

We conclude that routine pathologic evaluation of non-neoplastic kidney provides valuable diagnostic and prognostic information.

The Involvement of PDGF-B/PDGFRβ Axis in the Resistance to Antiangiogenic and Antivascular Therapy in Renal Cancer

BACKGROUND/AIM

Studies developed in the field of platelet-derived growth factors/platelet-derived growth factor receptors (PDGFs/PDGFRs) inhibition have focused on the therapeutic effects on tumor cells, neglecting their potential effects on tumor blood vessels. We herein propose a differential and critic assessment of platelet-derived growth factor B (PDGF-B) and platelet-derived growth factor receptor β (PDGFRβ) in renal cell carcinoma, correlated with the four main vascular patterns previously reported by our team.

MATERIALS AND METHODS

PDGF-B and PDGFRβ were evaluated on 50 archival paraffin embedded specimens related to vascular endothelial growth factor (VEGF), its inhibitory isoform VEGF165b and vascular patterns.

RESULTS AND CONCLUSION

Our results support the involvement of VEGF165b in the phosphorylation of PDGFRβ with an inhibitory effect on endothelial proliferation and migration. The simultaneous action of PDGF-B/PDGFRβ and VEGF165b on the same type of receptor may explain the resistance to antiangiogenic therapy, which depends on the degree of modulation of PDGFRβ phosphorylation.

VEGF receptor subtypes may serve as novel prognostic factors and putative indicators for anti VEGF receptor treatment response in renal cell carcinoma cases

PURPOSE

Targeted therapies are novel treatment options for renal cell carcinoma (RCC). Of the target molecules investigated, vascular endothelial growth factor receptors (VEFGRs) were seldom evaluated. The current study investigated the prognostic significance of VEGFRs and IMP-3 as a potential prognostic markers.

METHODS

Pathological material and clinical files of 100 patients with RCC were retrospectively evaluated. For each case, the clinical outcome and disease stage were assessed and resected materials were histologically reevaluated. VEGFR-2, VEGFR-3 and IMP-3 expression of tumor samples were analyzed with immunohistochemistry. These expressions were compared with prognosis and clinicopathological variables.

RESULTS

Five-year overall survival (OS) was 80% in the whole cohort. Mean survival was 20.3±1.9 months in metastatic disease (95%CI:16.4-24.2). Two-year OS was 20% and 5-year OS was zero in the metastatic group. Survival was significantly longer in VEGFR-2 expressing group than in the nonexpressing group (78.7±2.6 vs 63.9±6; 95%CI:73.7-84 and 52.1-75.7, respectively; p=0.031). VEGFR-3 and IMP-3 expressions were not significantly correlated with survival. In the non-metastatic group mean OS was 82.6±2.1 months and 2- and 5-year OS were 96 and 88%, respectively.

CONCLUSIONS

Since VEGFRs were expressed on all histological subtypes and significantly correlated with survival, assessment of VEGFR-2 and VEGFR-3 on tumor samples might serve as a putative prognostic factor in RCC cases. These expressions might identify a subset of patients that may benefit from antiangiogenic treatments targeting VEGFR receptors.

Metastasis of breast cancer to renal cancer: report of a rare case

Tumor-to-tumor metastasis (TTM) is a rare phenomenon. We present a case of an invasive ductal carcinoma (IDC) of the breast metastasizing to a clear cell renal cell carcinoma (RCC). Breast cancer (BC) metastasis to the RCC is rarely reported, especially in resected kidney tumor. In several cases reported, IDC was the exclusively histologic type of BC metastasized to RCC. It seems that the different molecular type of IDC doesn't affect the metastatic tendencies to RCC. TTM was an indicator of diffuse disease. For any patient with a history of breast cancer, especially with multi-organs metastasis, resection of kidney tumor should be carefully considered.

Mixed epithelial and stromal tumor of the kidney: report of a rare case and review of literature

Mixed epithelial and stromal tumor of the kidney (MESTK) is a rare benign tumor composed of epithelial and stromal cells. We report a rare male case with detailed clinicopathological data and follow-up information. The patient presented with gross hematuria. Computed tomography (CT) and magnetic resonance imaging study showed a 60 mm×40 mm cystic lesion with thickened septa and minimal contrast enhancement at the lower pole of the right kidney. The patient underwent nephron sparing surgery (NSS). Intraoperative frozen section showed benign histological features without significant cytologic atypia and mitosis. By additional immunohistochemistry investigations, the epithelial component was positive for cytokeratin-7, high molecular weight cytokeratin, and PAX-8. The stromal component showed strong positivity for vimentin and smooth-muscle actin. This case emphasizes that it is difficult to establish a precise diagnosis of MESTK preoperatively due to lack of any typical radiological features. Thus, intraoperative frozen section is of great clinical significance for NSS with preservation of kidney function. Additionally, regular follow-up is necessary for the MESTK with malignant potential.

Tubulocystic renal cell carcinoma with poorly differentiated foci is indicative of aggressive behavior: clinicopathologic study of two cases and review of the literature

Tubulocystic renal cell carcinoma (TCRCC) is a rare, recently characterized RCC subtype with distinctive clinicopathologic and genetic characterizations as well as typical behaviors in an indolent fashion. However, sporadic case reports in the literature have indicated that TCRCC with sarcomatoid differentiation or poorly differentiated (PD) foci could behave aggressively. Herein, we reported two cases of TCRCC with PD foci indentified from our consultative service. Both patients were male and aged 66 y and 47 y, respectively. The first patient experienced radical nephrectomy while the other was treated by partial nephrectomy. Macroscopically, both tumors were described as partly cystic and solid with the greatest diameter measuring of 12-cm and 4.5-cm, respectively. Histologically, both lesions had classic areas of TCRCC occupying most part of the tumor with small papillary RCC component. In case one, PD foci were scatteredly distributed and mixed with TCRCC and papillary RCC components, while in the other case the PD foci were adjacent to the areas of TCRCC. In both tumors, the PD foci were composed of irregular, often angulated, small tubules lined by atypical eosinophilic cells and surrounded by desmoplastic stroma, resembling collecting duct carcinoma. Immunohistochemistry, in both tumors, both TCRCC component and PD foci showed the similar immunoprofiles, i.e., labeling strongly and diffusely with PAX8, AMACR and Vimentin, and focally with CK34βE12 but not with renal cell carcinoma marker or P63. In case one, the tumor invaded extensively into the adjacent renal parenchyma and focally into both renal sinusal and perirenal adipose tissues. The patient had metastasis in the pelvic cavity at the time of diagnosis and succumbed to the disease without further treatment 3 months later. The other case was organ confined but with focal positive renal parenchymal margin. The patient subsequently underwent radical nephrectomy and was in a good status without evidence of tumor recurrence or metastasis at a follow-up of 8 months.

Validity of Tissue Microarray by Immunohistochemistry

BACKGROUND

Tissue microarrays (TMAs) extract designated areas of tissue paraffin blocks in several units that are millimeters in diameter in a cylindrical fashion, array dozens of these tissue specimens, and then re-embed them. Here, a TMA was utilized to analyze renal cell carcinoma (RCC) specimens with anti-FABP7 and anti-Brn2 antibodies.

METHODS

Paraffin-embedded specimens from 114 RCC patients were immunostained with anti-FABP7 and anti-Brn2 antibodies to examine the rate of agreement between the staining of TMA grafts compared to conventional tissue slice grafts. The staining area of the tumor was also examined.

RESULTS

The positive ratio of anti-FABP7 was 74% and of anti-Brn2 was 57%. The rate of agreement of each antibody was 100% regardless of tumor size before extraction.

CONCLUSIONS

Immunostaining of TMA slices might be effective for the analysis of RCC specimens.

Dynamic UltraFast 2D EXchange SpectroscopY (UF-EXSY) of hyperpolarized substrates

In this work, we present a new ultrafast method for acquiring dynamic 2D EXchange SpectroscopY (EXSY) within a single acquisition. This technique reconstructs two-dimensional EXSY spectra from one-dimensional spectra based on the phase accrual during echo times. The Ultrafast-EXSY acquisition overcomes long acquisition times typically needed to acquire 2D NMR data by utilizing sparsity and phase dependence to dramatically undersample in the indirect time dimension. This allows for the acquisition of the 2D spectrum within a single shot. We have validated this method in simulations and hyperpolarized enzyme assay experiments separating the dehydration of pyruvate and lactate-to-pyruvate conversion. In a renal cell carcinoma cell (RCC) line, bidirectional exchange was observed. This new technique revealed decreased conversion of lactate-to-pyruvate with high expression of monocarboxylate transporter 4 (MCT4), known to correlate with aggressive cancer phenotypes. We also showed feasibility of this technique in vivo in a RCC model where bidirectional exchange was observed for pyruvate-lactate, pyruvate-alanine, and pyruvate-hydrate and were resolved in time. Broadly, the technique is well suited to investigate the dynamics of multiple exchange pathways and applicable to hyperpolarized substrates where chemical exchange has shown great promise across a range of disciplines.

Combined use of COX-1 and VEGF immunohistochemistry refines the histopathologic prognosis of renal cell carcinoma

The course of RCC is asymptomatic, resulting in 25-30% of patients presenting with metastatic disease at time of diagnosis. The development of novel agents targeting angiogenesis and signal transduction pathways has improved patient outcomes. Role of cyclooxygenase in cancer development has been the subject of close scrutiny. COX-1 has been recognized to be involved in regulation of angiogenesis. To date, no immunohistochemical studies have been performed to assess the possible association between COX-1 and VEGF in RCC. This study is designed to evaluate the relationship between these two proteins in RCC. Also, the relationship between their combined immunohistochemical expression and different clinicopathological prognostic parameters in RCC is investigated. Immunohistochemical expression of COX-1 and VEGF was evaluated retrospectively on 64 cases of primary RCC including: 45 clear cell carcinoma, 12 papillary carcinoma and 7 of chromophope carcinoma. High COX-1 expression was detected in 62.5% of RCCs with a significant association with tumor grade (P=0.028), and highly significant relationship with tumor size and stage (P=0.001). There was a highly significant relationship between the VEGF score and tumor size (P=0.001), and stage (P=0.006). There was a positive correlation between COX-1 and VEGF expression score (P=0.001). Combined expression of both markers predicts high stage tumors (stage III/IV). Immunohistochemical expression of COX-1 and VEGF is associated with poor prognostic parameters in RCC. Their combined expression has a beneficial role in prediction of high stage tumors (III/IV).

Urothelial carcinoma with oncocytic features: an extremely rare case presenting a diagnostic challenge in urine cytology

Recognizing histological variants in urothelial carcinoma (UC) is important because some may be associated with different clinical outcomes and/or therapeutic approaches; being aware of unusual histological variants may also be crucial in preventing diagnostic misinterpretations. Histological variants based on cytoplasmic features, such as clear-cell, plasmacytoid, rhabdoid, and lipoid-rich variants, are described in invasive UC; however, these cytoplasmic features are not formally defined and not usually encountered in non-invasive UC. Oncocytic cytoplasm has not been well described in either invasive or non-invasive UC. Herein, we report an exceedingly rare case of UC with oncocytic features arising in the right renal pelvis, which presented a diagnostic challenge in urine cytology due to the relatively low nuclear-to-cytoplasmic ratio; however, it could definitively be diagnosed using histological specimens. UC diagnosis is based on the presence of papillary architecture and widespread p53 nuclear accumulation, suggesting malignancy. An oncocytic tumor is generally considered to be not actively dividing, as shown by the low Ki-67 labeling index in this case. In spite of the low proliferative activity, the possibility of intravesicle recurrence (IVR) should be considered since positive preoperative cytology of upper tract UC is a risk factor for IVR after nephroureterectomy.

Fat-forming solitary fibrous tumor of the kidney: a case report and literature review

Fat-forming solitary fibrous tumor (SFT) is a rare soft tissue tumor. Herein, we reported a 30-year-old woman was found to have a solid mass measuring 60×45 mm in the right kidney on an abdominal computed tomography scan. The tumor was well-circumscribed and composed of cellular nodules with the classic SFT admixed with clusters and lobules of mature adipocytes. Immunohistochemistry staining showed that the tumor cells were diffusely and strongly positive for CD34 and Bcl-2, focally and weakly positive for CD99 and EMA. Mature adipocytes were positive for S-100 protein. Ki-67 expression was found in approximately 2% of tumor cells. However, tumor cells were negative for cytokeratin, S-100 protein, HMB-45, Melan-A, SMA, and CD117. We made the pathological diagnosis of fat-forming SFT of the right kidney. The differential diagnosis includes angiomyolipoma, liposarcoma, spindle cell lipoma, sarcomatoid renal cell carcinoma, synovial sarcoma, and gastrointestinal stromal tumor. The patient was alive and well without evidence of recurrence or metastasis at 19 months after tumor resection.

Papillary renal cell carcinoma: a clinicopathological and whole-genome exon sequencing study

Papillary renal cell carcinoma (PRCC) represents the second most common histological subtype of RCC, and comprises 2 subtypes. Prognosis for type 1 PRCC is relatively good, whereas type 2 PRCC is associated with poor clinical outcomes. The aim of the present study was to evaluate the clinicopathological and mutations characteristics of PRCC. Hence, we reported on 13 cases of PRCC analyzed using whole-exome sequencing. Histologically, type 2 PRCC showed a higher nuclear grade and lymphovascular invasion rate versus type 1 PRCC (P < 0.05). Immunostaining revealed type 1 PRCC had higher CK7 and lower Top IIα expression rates (P < 0.05). Whole-exome sequencing data analysis revealed that the mutational statuses of 373 genes (287 missense, 69 silent, 6 nonsense, and 11 synonymous mutations) differed significantly between PRCC and normal renal tissues (P < 0.05). Functional enrichment analysis was used to classify the 287 missense-mutated genes into 11 biological process clusters (comprised of 61 biological processes) and 5 pathways, involved in cell adhesion, microtubule-based movement, the cell cycle, polysaccharide biosynthesis, muscle cell development and differentiation, cell death, and negative regulation. Associated pathways included the ATP-binding cassette transporter, extracellular matrix-receptor interaction, lysosome, complement and coagulation cascades, and glyoxylate and dicarboxylate metabolism pathways. The missense mutation status of 19 genes differed significantly between the groups (P < 0.05), and alterations in the EEF1D, RFNG, GPR142, and RAB37 genes were located in different chromosomal regions in type 1 and 2 PRCC. These mutations may contribute to future studies on pathogenic mechanisms and targeted therapy of PRCC.

[Clinicopathologic study of primary renal hemangioblastoma]

OBJECTIVE

To study the clinicopathologic characteristics of primary renal hemangioblastoma.

METHODS

The morphologic features, immunophenotype and molecular findings of 3 cases of primary renal hemangioblastoma were studied, with review of literature.

RESULTS

The age of patients ranged from 43 to 57 years. There were 2 women and a man. The patients often presented with renal mass. Histologically, the tumors were surrounded by thick fibrous capsule and composed of epithelioid or spindle cells. Two cases had a prominent stromal component and the other one was rich in capillary network. Lipid vacuoles were observed in all cases. Features of hemorrhage were demonstrated in 2 cases. Capsular invasion and necrosis were seen in 1 case. Immunohistochemical study showed that the stromal cells were positive for alpha-inhibin (3/3), S-100 protein (3/3), EGFR (2/2), PAX-2 (2/2), PAX-8 (2/2) and CA9 (2/2) but negative for CKpan (2/2) and HMB45 (2/2). Focal membranous staining for CD10 (3/3) was noted. No VHL gene mutations or chromosome 3p deletion were detected in the 2 cases studied.

CONCLUSIONS

Renal hemangioblastoma shows distinctive morphologic appearance with a wide range of variation. The unexpected positive staining for PAX-2, PAX-8 and CD10 in renal hemangioblastoma needs to be aware. Immunohistochemical study may be helpful in differential diagnosis of these renal tumors.

Primary renal diffuse large B-cell lymphoma with central nervous system involvement: a rare case report and literature review

Primary renal lymphoma is a rare entity. Of these, diffuse large B-cell lymphoma is the most common pathological type and, R-CHOP regimen was the preferred chemotherapy for it. Here we present an adult case of primary renal diffuse large B-cell lymphoma.

[Clear cell papillary renal cell carcinoma: a distinct low-grade renal tumour]

OBJECTIVE

To study the clinicopathologic features of clear cell papillary renal cell carcinoma (CCPRCC).

METHODS

The clinical, morphologic and immunohistochemical characteristics of 6 cases of CCPRCC were reviewed, with analysis of follow-up data.

RESULTS

There were altogether 3 men and 3 women. The mean age of patients was 56 years. The size of tumors ranged from 1.0 to 4.5 cm in greatest dimension. They had solid or solid-cystic cut surface. Histologically, the tumors were encapsulated and showed several morphologic patterns, with tubules, papillae, acini, interconnecting ribbons and macro/microcysts lined by single layer of cells with clear or small amount of eosinophilic cytoplasm and low-grade nuclei (corresponding to Fuhrman grade 1 or 2). Mitotic figures were rarely seen. Characteristically, there was linear arrangement of the nuclei away from the basement membrane, conferring an appearance similar to that of endometrial glands in early secretory phase. Tubules and cysts contained serosanguineous fluid or colloid-like secretion were identified. No foamy histiocytes, psammomatous calcifications or hemosiderin was present in the papillary areas. Two of the tumors showed focal or extensive angioleiomyoma/leiomyoma-like components. No coagulative necrosis, sarcomatoid dedifferentiation, nor microscopic vascular invasion was observed. Immunohistochemically, all tumors showed strong co-expression of CK7 and CA9 (with characteristic "goblet" staining pattern). The staining for EMA, CK (AE1/AE3), vimentin, CK8, CK18, CK19 and PAX-8 were also positive in all cases. Ki-67 was expressed in less than or about 5% of the tumor cell nuclei. The staining for CD10, P504S, CD117, TFE3 and TFEB was negative. Follow-up data were available in all patients, with mean duration of 14 months (range = 7 to 27 months). All of the patients were disease-free after operation.

CONCLUSION

CCPRCC is a special type of low-grade renal neoplasm with characteristic histopathologic and immunohistochemical features. It needs to be distinguished from clear cell renal cell carcinoma or papillary renal cell carcinoma.

Quiz. Correct answer to the quiz. Check your diagnosis. Clear cell papillary renal cell carcinoma

We incidentally observed a case of clear cell papillary renal cell carcinoma of an 81-year-old woman, presenting with intermittent left flank pain. It is a recently described rare renal parenchymal tumor.

Immunohistochemical phenotype and molecular pathological characteristics of metanephric adenoma

To assess the clinicopathological, immunohistochemical and molecular features of metanephric adenoma (MA). Clinicopathologic data were obtained for 5 cases of MA with follow-up information. Specimens from these patients were stained by HE and immunohistochemistry for the detection of WT1, vimentin, S-100 protein, CK7, P504s, CD10 and renal cell carcinoma marker (RCC). Fluorescence in situ hybridization (FISH) was performed on 4 tumors. The patients included 1 male and 4 females, aged from 30 to 49 (mean=39) years. Tumor diameters ranged from 3 to 5.5 cm. Histologically, the tumors had tubular, papillary, or glomeruloid architectures, and were composed of cells with uniform and round nuclei, inconspicuous nucleoli, and high ratio of nucleus to cytoplasm. Nuclear polymorphism and mitotic figures were not observed. Immunohistochemically, they expressed WT1 (5/5), vimentin (5/5), S-100 (4/5), CK7 (2/5), P504s (2/5), and CD10 (1/5) and not RCC. FISH study was carried out on 4 metanephric adenoma cases, and no abnormalities were observed in chromosomes 3, 7, 17, and P16 gene of chromosomes 9. MA is an uncommon renal tumor. Its diagnosis depends on morphological, immunohistochemical and molecular features.

Coexistence of multiple myeloma and clear cell renal cell carcinoma: a case report and review of literature

Coexistence of multiple myeloma (MM) and renal cell carcinoma (RCC) is an extremely rare condition. Nevertheless, there is a higher than expected incidence of co-occurrence of these two malignancies. Several case series, in the recent past, have postulated an association between MM and RCC. Population-based data analyses have revealed a bi-directional association between these two malignancies. However, the cause still remains speculative up to date. Here, we aim to describe a patient with MM and clear cell renal cell carcinoma (CCRCC) one after another for the second time from China. Clinical implications are discussed with a critical review of existing literature and we expect to draw much more awareness among clinicians regarding such association.

Distribution study of cisplatin in rat kidney and liver cancer tissues by using liquid chromatography electrospray ionization tandem mass spectrometry

A sensitive and rapid liquid chromatography positive ion electrospray ionization tandem mass spectrometric (LC/ESI-MS/MS) method has been developed and validated for the quantitative determination and distribution of cisplatin (CP) in kidney and liver tissues after intravenous administration of drug to adult male Sprague Dawley rats. Oxaliplatin (OXP) was used as an internal standard. The tissue samples were homogenized and extracted using conventional liquid-liquid extraction method with phosphate buffer containing ethyl acetate and then subjected to LC-MS analysis. The chromatographic separation was achieved on an Agilent ZORBAX SB C-18 column (50 × 2.1 mm, 1.8 µm) using the mobile phase consisting of 0.1% formic acid in water (Solvent A) : methanol (Solvent B) (40 : 60; v/v) in an isocratic elution followed by detection with positive ion electrospray ionization tandem mass spectrometry using the transitions of m/z 301 > 265 for CP and m/z 398 > 310 for OXP in multiple reaction monitoring mode. The calibration curve was linear in the range of 5.0-7000 and 10.0-6000 ng/ml for kidney and liver tissue homogenates, respectively. The method revealed good performances in terms of within-batch, between-batch precision (1.31-5.70%) and accuracy (97.0-102.24%) for CP in both kidney and liver tissue homogenates including lower and upper limits of quantification. The recoveries from spiked control samples were >81.0% and >87.0 % for CP and OXP, respectively. Matrix effect was found to be negligible, and the stability data were within the acceptable limits. Further, the validated LC/ES-MS/MS method was successfully applied to investigate the distribution of CP in kidney and liver tissues after intravenous administration of CP to male Sprague Dawley rats. The results showed that the higher amount of CP was distributed in kidney followed by liver, which indicated that CP mainly accumulated in kidney tissues and renal excretion might be a primary and main elimination route. This is the first research approach focused on the quantitative determination and distribution of CP in rat kidney and liver tissue homogenates by using LC/ESI-MS/MS, which could provide essential information for further pharmacological and clinical studies of CP.

Clear cell papillary renal cell carcinoma: a clinicopathologic analysis of 6 cases

Clear cell papillary renal cell carcinoma (CCPRCC) is a newly described variant of renal cell carcinoma (RCC) which is composed mainly of cells with clear cytoplasm arranged in cystic and papillary patterns. We report the clinicopathologic features, prognosis and differential diagnosis of 6 Clear Cell Papillary Renal Cell Carcinomas. The clinical information and follow-up data were analyzed. The patients were six males with median age of 52.5 years. Case 1 revealed dense calcification and ossification. Cases 2 and 3 contain a variably prominent smooth muscle stromal component. CA-IX, CK7, PAX-8 and VIM were positive in all cases. TFE3 and AMACR were not expressed in any tumor. CD10 was negative in 5 of 6 cases .The patients were followed for 13~55 months with no local tumor recurrences and tumor metastasis. The CCPRCC was associated with a more favorable outcome. These were low-grade and low-stage renal tumors. No lymph node or distant metastasis of the six tumors.

[Prognostic factors and efficacy of molecular targeted therapy for metastatic clear cell renal cell carcinoma]

We retrospectively reviewed the medical records of patients with metastatic clear cell renal cell carcinoma who received molecular targeted therapy between 2005 and 2011. Cancer-specific survival was analyzed using the Kaplan-Meier method. Predictors of cancer-specific survival were analyzed using the Cox regression hazards model. A total of 89 patients, consisting of 50 first line patients and 39 patients receiving prior cytokine were included in the analysis. The two-year cancer-specific survival rate of the firstlinegroup was 60.2% and that of theprior cytokinethe rapy group was 62.1%. In univariateanalysis, Karnofsky performance status (KPS)＜80%, time from diagnosis to treatment less than one year, bone metastasis and C-reactive protein (CRP)＞1.3 mg/dl in were statistically significant prognostic factors (p＜0.05). In multivariate analysis, time from diagnosis to treatment less than one year (HR 2.46, 95%CI 1.11-5.82, p＝0.025) and CRP (HR 4.92, 95%CI 2.23-11.3, p＜0.001) were independent prognostic factors. Time from diagnosis to treatment less than one year and CRP were independent prognostic factors in patients who received molecular targeted therapy.

Expression and significance of FOXP1, HIF-1a and VEGF in renal clear cell carcinoma

PURPOSE

To investigate the expressions of FOXP1, hypoxia inducible factor (HIF)-1a and vascular endothelial growth factor (VEGF) in renal cell carcinoma of the clear type (CCRCC) and their relationship with the patient clinicopathological features.

METHODS

The expressions of forkhead box-P1 (FOXP1), HIF-1a and VEGF in 55 cases of CCRCC tissues were determined using immunohistochemistry. Then, their correlations with clinical stage, histological grade and lymph node metastasis were analyzed using chi-square test.

RESULTS

Thirty-seven of the 55 cases (67.3%) of CCRCC expressed FOXP1 with an abnormal expression rate of 38.2% (21/55), in which there were 10 cases with positive FOXP1 both in the nucleus and the cytoplasm and 11 cases with positive FOXP1 in cell membrane. The abnormal expression rate of FOXP1 inhigh grade CCRCC (G3/G4) was significantly higher than that in low grade CCRCC (G1/G2, p<0.05). FOXP1 expression was significantly correlated with the expression of HIF1 and VEGF (r=0.54, p<0.01 and r=0.37, p<0.05, respectively), but was not obviously correlated with clinical stage, lymph node metastasis and 5-year overall patient survival (p>0.05).

CONCLUSION

Abnormal expression of FOXP1 and its deficiency are common events in CCRCC. Abnormal expression of FOXP1 may create progression of tumor from low grade to high grade by regulating the HIF-1-VEGF pathway.

Decreased ARID1A expression correlates with poor prognosis of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (CCRCC) is the most common renal cell carcinoma. It has a relatively unfavorable prognosis compared to other common renal cell carcinomas. Recently, comprehensive molecular studies in CCRCC revealed important genetic alterations, including changes in the VHL, PBRM1, and ARID1A genes. The expression of ARID1A protein is associated with tumor progression and prognosis in many cancers. This study aimed to evaluate the nuclear expression of ARID1A in CCRCC and to assess its expression with the clinical prognosis. The nuclear expression of ARID1A was evaluated in 290 cases of CCRCC by immunohistochemistry. To determine the clinicopathological association with ARID1A, each of the cases was divided into 2 groups, low- and high-expression groups, according to the average proportion of nuclear staining. Decreased ARID1A expression was associated with the higher nuclear grade and higher pTNM stage (P < .001 and P = .013, respectively). The ARID1A low-expression group revealed significantly shorter cancer-specific and progression-free survival times (P = .001 and P < .001, respectively). Furthermore, Cox regression analysis showed that ARID1A expression was an independent prognostic factor for progression-free survival (P = .009). These results suggest that nuclear expression of ARID1A may serve as a new prognostic marker in CCRCC patients.