Genitourinary cytopathology (kidney and urinary tract)

Deconvolution of Human Urine across the Transcriptome and Metabolome

BACKGROUND

Early detection of the cell type changes underlying several genitourinary tract diseases largely remains an unmet clinical need, where existing assays, if available, lack the cellular resolution afforded by an invasive biopsy. While messenger RNA in urine could reflect the dynamic signal that facilitates early detection, current measurements primarily detect single genes and thus do not reflect the entire transcriptome and the underlying contributions of cell type-specific RNA.

METHODS

We isolated and sequenced the cell-free RNA (cfRNA) and sediment RNA from human urine samples (n = 6 healthy controls and n = 12 kidney stone patients) and measured the urine metabolome. We analyzed the resulting urine transcriptomes by deconvolving the noninvasively measurable cell type contributions and comparing to plasma cfRNA and the measured urine metabolome.

RESULTS

Urine transcriptome cell type deconvolution primarily yielded relative fractional contributions from genitourinary tract cell types in addition to cell types from high-turnover solid tissues beyond the genitourinary tract. Comparison to plasma cfRNA yielded enrichment of metabolic pathways and a distinct cell type spectrum. Integration of urine transcriptomic and metabolomic measurements yielded enrichment for metabolic pathways involved in amino acid metabolism and overlapped with metabolic subsystems associated with proximal tubule function.

CONCLUSIONS

Noninvasive whole transcriptome measurements of human urine cfRNA and sediment RNA reflects signal from hard-to-biopsy tissues exhibiting low representation in blood plasma cfRNA liquid biopsy at cell type resolution and are enriched in signal from metabolic pathways measurable in the urine metabolome.

The Paris System "atypical urothelial cells" category: can the current criteria be improved?

INTRODUCTION

The Paris System (TPS) for reporting urine cytology was developed for standardization of diagnosis focusing on the detection of high-grade urothelial carcinoma (HGUC). Probably the most challenging task for TPS is to provide criteria for the atypical urothelial cell (AUC) category. The TPS criteria for AUC include increased nuclear/cytoplasmic (N/C) ratio (>0.5) and 1 of the 3 minor criteria including nuclear hyperchromasia (NH), coarse chromatin (CC) and irregular nuclear membrane (INM). We evaluated TPS-AUC diagnostic value and investigated whether other morphologic parameters can improve its criteria.

MATERIALS AND METHODS

Urine samples with diagnoses of AUC collected during a 6-month period were re-reviewed. Data captured included N/C ratio >0.5, NH, CC, INM, and 2 additional criteria including enlarged nuclear size (ENS) and the presence of nucleolus (N). ENS was considered when the nucleus was 2 times larger than the urothelial cell or 3 times larger than lymphocyte.

RESULTS

By applying the TPS-AUC criteria, the rate of atypia diagnosis reduced in comparison to Pre-TPS (9% versus 13%, P = 0.02). Among the AUC minor criteria, NH was the best criterion with the highest interobserver agreement (IOA) and correlation with HGUC (k = 0.342, r = 0.61, P < 0.001) and strong PPV (93.6%). ENS had the highest PPV (95.8%) and, after NH, had the highest IOA and correlation with HGUC (k = 0.29, r = 0.52, P < 0.001).

CONCLUSION

TPS improves the diagnostic value of urine cytology, particularly in cases with atypia. ENS is a strong criterion for increasing the diagnostic value of AUC and potentially can improve TPS performance as a minor criterion.

A novel diagnostic tool for the detection of bladder cancer: Measurement of urinary high mobility group box-1

OBJECTIVE

We aimed to investigate the diagnostic value of urinary High Mobility Group Box-1 (HMGB1) level as a noninvasive tool that can be potentially used for diagnosis and during follow-up in patients with bladder cancer patients.

METHOD

The study was conducted in a total of 121 participants including 61 patients diagnosed with primary bladder cancer, 30 patients with an acute urinary tract infection and 30 healthy controls. Age, gender and urinary HMGB1 levels of the study groups were evaluated. The association of clinical features (tumor diameter, number of foci, pathological grade, muscle invasion) with urinary HMGB1 levels was investigated in patients with bladder cancer.

RESULTS

All 3 groups showed a normal age and gender distribution with no significant difference among them (P = 0.775 and P = 0.967, respectively). A significant difference was detected in urinary HMGB1 levels among the 3 groups (P < 0.001). When urinary HMGB1 levels were compared between patients with high grade vs. low grade tumors, the mean HMGB1 level was 44.39 pg/ml (12.1-505.2) in patients with low grade tumors and 280 pg/ml (18.7-2685.3) in patients with high grade tumors (P < 0.001). Patients with a greater number of tumor foci had higher HMGB1 levels in comparison to patients with a single tumor focus (P = 0.008). Urinary HMGB1 levels were higher in patients with a tumor diameter of ≥3 cm than in patients with a tumor diameter less than 3 cm (P = 0.001). Patients with muscle-invasive bladder cancer exhibited higher urinary HMGB1 levels compared to patients with non-muscle-invasive bladder cancer (P = 0.033). The cut-off values derived from the ROC analysis were 63.30 pg/ml for distinguishing bladder cancer from urinary tract infection, 30.94 pg/ml for urinary tract infection versus control group and 38.70 pg/ml for bladder cancer vs. control group, respectively. Sensitivity was 59% and specificity was found 77%.

CONCLUSION

In future controlled studies involving larger patient groups, urinary HMGB1 levels can be used for diagnostic and screening purposes in bladder cancer patients.

Evidence-based adequacy criteria for urinary bladder barbotage cytology

INTRODUCTION

Adequacy criteria are well established in some areas of cytopathology to prevent false negative diagnoses. To date, no such criteria have been proposed and validated for urinary tract specimens. Our aim was to determine a cellularity cutoff point that significantly affects the sensitivity of detecting high-grade or in situ urothelial carcinoma (HGUC or UCIS) in bladder barbotage/washing specimens.

MATERIALS AND METHODS

Bladder barbotage specimens collected in liquid-based media were selected. Specimens diagnosed as "positive for HGUC" (with histologic confirmation) composed the study group, with negative cases as control specimens. Samples were serially diluted and ThinPrep slides of decreasing cellularity were made and reviewed for diagnosis and cellularity. In a retrospective validation study, we identified cases with a "negative for malignancy" bladder barbotage/washing and a surgical pathology diagnosis of UCIS or HGUC (ie, false negative cytology). Cellularity was assessed.

RESULTS

A distinct difference in sensitivity was noted at a cutoff point of 2644 (20 per 10 high-power fields) urothelial cells. Sensitivities increased for atypical or higher (68.3% versus 100%) and HGUC (43.3% versus 88.0%) after application of this cutoff point with high statistical significance (P = 0.001 and 0.0001, respectively). For the retrospective review, cases below the cutoff point were reclassified as unsatisfactory, and sensitivity rose from 76.3% to 84.8% (P = 0.0027).

CONCLUSIONS

Our results indicate that, in the absence of atypical or malignant cells, an adequate bladder barbotage specimen should have a minimum of 2644 (20 per 10 high-power fields) well-visualized, well-preserved urothelial cells to increase the positive predictive value of this test.

What should not be reported as atypia in urine cytology

The term "atypia," although not well characterized, is widely used in diagnostic surgical and cytopathology. Because there are no guidelines regarding when to use this term, in the majority of cases, it is used as a "wastebasket." This definitely applies to urine cytology, where the reported rate of atypia ranges from 1.9% to 23%. This review lists a number of cytomorphologic findings in urine cytology that are associated with known and specific causes. Urine specimens in which the morphologic changes can be attributed to particular etiologic factors should no longer be classified as "atypical." These include urine specimens showing reactive umbrella cells or seminal vesicle cells, reactive changes due to stones, cytologic changes characteristic of infectious processes or therapy effect, instrumented urines with pseudopapillary clusters, and urinary diversion specimens.

Is a consistent cytologic diagnosis of low-grade urothelial carcinoma in instrumented urinary tract cytologic specimens possible? A comparison between cytomorphologic features of low-grade urothelial carcinoma and non-neoplastic changes shows extensive overlap, making a reliable diagnosis impossible

INTRODUCTION

The ability to consistently diagnose low-grade urothelial carcinoma (LGUC) in urinary tract cytology (UTCy) specimens remains controversial, as the reported sensitivity of UTCy in the detection of LGUC is as low as 10%. To determine whether a consistent cytologic diagnosis of LGUC is possible, we assessed the presence and frequency of previously described cytomorphologic features of LGUC in UTCy from patients with LGUC and a negative control group.

MATERIALS AND METHODS

Biopsy-proven cases of LGUC from June 1, 2010 to January 31, 2014 were identified; UTCy obtained within 3 months prior to biopsy composed the study group (n = 98). The negative control group consisted of UTCy obtained from patients with negative cystoscopy and biopsy (n = 53). All specimens were masked and reviewed in random order to evaluate 17 cytomorphologic parameters.

RESULTS

Univariate statistical analyses demonstrated that the prevalence of paired cells, clumpy chromatin, and cytoplasmic homogeneity was higher in the study group; however, multivariate analysis did not show these features as significant predictors of LGUC.

CONCLUSIONS

No cytomorphologic feature was statistically significant in the LGUC group versus the negative control group. The presence of 3-dimensional papillary structures with fibrovascular cores is diagnostic of LGUC, but it is only seen in a small minority (2 of 98) cases. Our results reemphasize the fact that urinary tract cytology has a low sensitivity for the diagnosis of LGUC and suggest that, instead of striving to detect LGUC in urine specimens, we should concentrate on the clinically relevant goal of urine cytology-the detection of high-grade lesions.

Renal paraganglioma: report of a case managed by robotic assisted laparoscopic partial nephrectomy and review of the literature

We describe the pathological and clinical presentation of a rare case of renal paraganglioma occurring as an incidental left renal mass in a 58-year-old woman. The patient underwent robotic assisted laparoscopic partial nephrectomy, which is the first one in the literature.