Benign-appearing urothelial tissue fragments in noninstrumented voided urine specimens are associated with low rates of urothelial neoplasia

Large-scale validation study of an improved semiautonomous urine cytology assessment tool: AutoParis-X

BACKGROUND

Adopting a computational approach for the assessment of urine cytology specimens has the potential to improve the efficiency, accuracy, and reliability of bladder cancer screening, which has heretofore relied on semisubjective manual assessment methods. As rigorous, quantitative criteria and guidelines have been introduced for improving screening practices (e.g., The Paris System for Reporting Urinary Cytology), algorithms to emulate semiautonomous diagnostic decision-making have lagged behind, in part because of the complex and nuanced nature of urine cytology reporting.

METHODS

In this study, the authors report on the development and large-scale validation of a deep-learning tool, AutoParis-X, which can facilitate rapid, semiautonomous examination of urine cytology specimens.

RESULTS

The results of this large-scale, retrospective validation study indicate that AutoParis-X can accurately determine urothelial cell atypia and aggregate a wide variety of cell-related and cluster-related information across a slide to yield an atypia burden score, which correlates closely with overall specimen atypia and is predictive of Paris system diagnostic categories. Importantly, this approach accounts for challenges associated with the assessment of overlapping cell cluster borders, which improve the ability to predict specimen atypia and accurately estimate the nuclear-to-cytoplasm ratio for cells in these clusters.

CONCLUSIONS

The authors developed a publicly available, open-source, interactive web application that features a simple, easy-to-use display for examining urine cytology whole-slide images and determining the level of atypia in specific cells, flagging the most abnormal cells for pathologist review. The accuracy of AutoParis-X (and other semiautomated digital pathology systems) indicates that these technologies are approaching clinical readiness and necessitates full evaluation of these algorithms in head-to-head clinical trials.

Uncovering additional predictors of urothelial carcinoma from voided urothelial cell clusters through a deep learning-based image preprocessing technique

BACKGROUND

Urine cytology is commonly used as a screening test for high-grade urothelial carcinoma for patients with risk factors or hematuria and is an essential step in longitudinal monitoring of patients with previous bladder cancer history. However, the semisubjective nature of current reporting systems for urine cytology (e.g., The Paris System) can hamper reproducibility. For instance, the incorporation of urothelial cell clusters into the classification schema is still an item of debate and perplexity among expert cytopathologists because several previous works have disputed their diagnostic relevance.

METHODS

In this work, an automated preprocessing tool for urothelial cell cluster assessment was developed that divides urothelial cell clusters into meaningful components for downstream assessment (ie, population-based studies, workflow automation).

RESULTS

In this work, an automated preprocessing tool for urothelial cell cluster assessment was developed that divides urothelial cell clusters into meaningful components for downstream assessment (ie, population-based studies, workflow automation). Results indicate that cell cluster atypia (i.e., defined by whether the cell cluster harbored multiple atypical cells, thresholded by a minimum number of cells), cell border overlap and smoothness, and total number of clusters are important markers of specimen atypia when considering assessment of urothelial cell clusters.

CONCLUSIONS

Markers established through techniques to separate cell clusters may have wider applicability for the design and implementation of machine learning approaches for urine cytology assessment.

The Diagnostic Dilemma of Urothelial Tissue Fragments in Urinary Tract Cytology Specimens

Since the release of The Paris System for Reporting Urinary Cytology (TPS), the assessment of urine cytology specimens has primarily focused on the detection of high-grade urothelial carcinoma (HGUC) and carcinoma in situ (CIS). Fortunately, the malignant cells in these lesions tend to be loosely cohesive, resulting in the natural exfoliation of individual malignant cells into the urine. However, HGUC/CIS lesions occasionally exfoliate larger fragments which can be difficult to assess due to cellular overlap and fragment three-dimensionality. Furthermore, reactive benign urothelial fragments and fragments from low-grade urothelial neoplasms (LGUN) may also be seen in urine specimens and contain atypical cytomorphologic features. As a result, the significance of urothelial tissue fragments (UTFs) is often unclear. Herein, we discuss the literature on UTFs before and after the implementation of TPS, as well as strategies to help overcome this diagnostic challenge.

Indeterminate atypia in urinary tract cytology: Does it really matter?

The study of atypia in urinary cytology has been ongoing for decades but most studies have focused primarily on test performance in patients with concurrent biopsies and/or limited follow-up periods. While these data are useful, many studies fail to consider patient factors that may alter the pretest probability, which can subsequently affect test performance. An isolated diagnosis of malignancy in urinary cytology usually has a high positive predictive value and allows a urologist to conduct a rigorous workup of the patient to establish a tissue diagnosis. However, it is less certain how an atypical diagnosis impacts patient care, given that many patients have a history of bladder cancer and are already under surveillance with cystoscopy at regular screening intervals. Furthermore, a discrete negative urine cytology is unlikely to allow a patient to forego a cystoscopy procedure due to limitations in the sensitivity of urine cytology. Over the last several years, the introduction of The Paris System for Reporting Urinary Cytology (TPS) has improved the predictive value of atypical diagnoses, but additional studies are needed to evaluate the performance of these diagnoses in specific clinical situations. Such data could better inform urologists on how to manage patients with atypical diagnoses. This review discussed the diagnosis of atypia in urinary cytology and the impact of such a diagnosis in various clinical contexts.

Applicability of the Paris System for veterans: high rates of undiagnosed low-grade urothelial neoplasia

BACKGROUND

The Paris System for Reporting Urinary Cytology (TPS) is a recently developed standardized terminology system. It is well-established that urine cytology has low sensitivity for detecting low-grade urothelial neoplasia (LGUN). Though the majority of tumors are low-grade, surveillance of these lesions is important to monitor for possible progression. Herein, we compared TPS to our veteran integrated system network (VISN) to assess its applicability. We also introduced semi-quantitative scoring to further evaluate cytomorphologic features of high-grade urothelial carcinoma (HGUC).

MATERIALS AND METHODS

Voided and instrumented urine cytology specimens and concurrent biopsies were reviewed from Sept 2018 - Jan 2020. Cytologic diagnoses reported using the VISN institutional system were reevaluated by staff cytopathologists and categorized according to TPS. A semi-quantitative scoring system to evaluate cytomorphologic features was devised.

RESULTS

Cytology and surgical specimens from 105 patients were reviewed. The VISN and TPS reporting systems were compared and showed similar sensitivities and specificities for the detection of HGUC. Rates of biopsy-proven LGUN were high for the negative for high-grade urothelial carcinoma category (NHGUC; 27/53, 50.9%) and atypical urothelial cells (AUC; 14/30; 46.7%) compared to suspicious/positive (0/22, 0%) categories. Major and minor criteria as outlined in TPS were evaluated semi-quantitatively.

CONCLUSIONS

Urine cytology has limited sensitivity for LGUN regardless of the cytologic reporting system used. There was a high rate of LGUN following NHGUC/AUC diagnoses in the Veteran population. Coarse chromatin was determined to be the least sensitive criterion for the detection of high-grade lesions and irregular chromatin rim was most specific.

Architectural aspects of cell-blocks as small biopsies

Cell-block preparations have become an essential part of integrated cytology diagnosis. They are essentially microbiopsies that are formalin fixed and embedded in paraffin. This has become more prevalent with greater sample procurement due to the advent of newer biopsy techniques and needles. Cell-blocks allow retrieval of small tissue fragments from cytology specimens that sometimes cannot be processed by alternate cytologic techniques. They represent concentrated, cell-enriched preparations that provide cytologists with the opportunity to evaluate cellular architecture, as well as to perform ancillary testing. A cell-block compatible sample may thus obviate the need for a more invasive procedure such as a tissue biopsy. Microscopic examination of cell-blocks is quick, avoids obscuring material, permits cells to be evaluated in one focal plane, and allows the histologic architecture such as glandular differentiation, papillary formations, and sometimes invasion to be easily identified. This new era of “cytohistology” accordingly requires practicing cytologists to become more familiar with histopathology. This review article discusses the benefit of various architectural patterns identifiable in cell-blocks employed as an adjunct to Pap tests, exfoliative fluid specimens, and fine-needle aspirations.

A review of upper urinary tract cytology performance before and after the implementation of The Paris System

Urinary cytology (UC) is one of the primary diagnostic modalities used for the screening and surveillance of urothelial carcinoma. Despite its widespread use, UC has suffered from a lack of standardized or reproducible criteria and wide interobserver variability, particularly of the designation of atypical urothelial cells. The Paris System for Reporting Urinary Cytology (TPS), published in 2016, aimed to provide a standardized approach for evaluating UC by creating diagnostic categories with specific cytomorphologic criteria. Recent studies have primarily investigated the application of TPS on lower urinary tract specimens and have mostly shown that TPS implementation has improved the performance of UC specimens. Only a few studies have reported the impact of TPS on upper urinary tract (UUT) cytology. Additionally, there is uncertainty as to which cytological features are most predictive of high-grade urothelial carcinoma (HGUC) in the UUT. This review summarizes the literature regarding the utility and performance of UUT cytology and highlights findings before and after the implementation of TPS.

A review of urinary cytology in the setting of upper tract urothelial carcinoma

Urothelial carcinomas of the upper urinary tract (UUT) are uncommon. Cytological examination of voided urine or washings from the UUT has been part of the standard workup for upper tract urothelial carcinoma (UTUC); however, its value remains controversial. The lack of uniform terminology and specific diagnostic criteria could also have contributed to the inferior performance of urinary cytology for detecting UTUC. The Paris System for Reporting Urinary Cytology (TPS) has provided a standardized reporting system for urinary cytology specimens with clearly defined cytomorphologic diagnostic criteria and found acceptance on an international level after its implementation in 2016. Recent studies have shown that TPS has led to improved diagnostic performance of urinary cytology; however, most of these studies had focused on the evaluation of lower urinary tract cytology specimens. Only a limited number of new research studies have analyzed the effect of TPS when applied to UUT cytology specimens. In the present report, we have summarized the current understanding and utility of UTUC, including its molecular biology, and reviewed the current literature.

Diagnostic Advances in Urine Cytology

The utility of urine cytology has shifted from the identification of red blood cells, crystals, or parasites to its currently used role of detection of cancer cells exfoliated in urine samples. A variety of ancillary tests have been developed to complement the diagnostic ability of urine cytology. Furthermore, urine testing will continue to evolve as the pathogenesis of genitourinary tract diseases in depth is understood. This article focuses on the diagnostic advances in urine cytology from the cytomorphological perspective, past and current reporting schemes, and the application of ancillary testing in urine samples.

The Paris System for Reporting Urinary Cytology: early review of the literature reveals successes and rare shortcomings

The Paris System for Reporting Urinary Cytology (TPS) provides recommendations for the diagnosis of urinary tract cytology (UTC) specimens and has found acceptance on an international level. Since the official release of TPS in 2016, numerous research studies have been published analyzing its impact. This review summarizes the studies published since the release of TPS, highlighting areas in which TPS has performed well and other areas in which TPS may need improvement.

A review of the Paris system for reporting urinary cytology

After the 2013 International Congress of Cytology in Paris, consensus groups were formed to establish an international reporting system for urinary tract (UT) specimens. The recommended guidelines, known as The Paris System (TPS) for Reporting Urinary Cytology, focus on reducing the rate of unnecessary indeterminate diagnoses while maintaining the excellent performance UT cytology has for identifying high-grade urothelial carcinoma. This review highlights the major features of TPS.

Use of vimentin immunocytochemical staining for evaluation of atypical cells in voided urine samples

BACKGROUND

Cytomorphology of exfoliated atypical reactive/repair renal tubular cells (RRTC) can resemble atypical urothelial cells thus suggesting a differential diagnostic question of urothelial neoplasia in urinary cytology. Vimentin expression has been shown in RRTC and used for differentiation from atypical urothelial cells.

METHODS

The institutional computer database was searched for urinary cytology cases with vimentin immunocytochemical staining (2008-2012). Original cytopathological diagnoses based on cytomorphology and the results of vimentin immunostaining were compared to follow-up data, including histopathological diagnosis, subsequent urinary cytopathology reports, and clinical findings.

RESULTS

Of the 42 cases with vimentin immunocytochemical staining, 33 were positive and 9 negative. Consequently, significant renal disease was found in 9/33 (27%) of vimentin positive cases and nehrolithiasis in 4/33 (12%) of vimentin positive and 1/9 (11%) of vimentin negative cases. Erythrocyturia of undetermined origin was diagnosed in nine cases (seven vimentin positive and two negative). Urinary cytology follow-up was negative in three vimentin positive cases. Urothelial carcinoma was found in 3/9 (30%) of vimentin negative cases. Thirteen patients were lost to follow-up.

CONCLUSIONS

Vimentin immunocytochemical staining could be used as an ancillary method for evaluation of atypical cells in urinary specimens in selected cases with RRTC exhibiting cytological atypia. Unnecessary diagnostic procedures for evaluation of urothelial carcinoma could be avoided in vimentin positive cases and further diagnostic work-up for evaluation of a significant renal disease could be suggested in vimentin positive cases. Diagn. Cytopathol. 2017;45:85-90. © 2016 Wiley Periodicals, Inc.

Impact of Implementing the Paris System for Reporting Urine Cytology in the Performance of Urine Cytology: A Correlative Study of 124 Cases

OBJECTIVES

We assessed the performance of urine cytology using the Paris System for Reporting Urine Cytology (PSRUC) in comparison to our current system.

METHODS

In total, 124 specimens with histologic correlation were reviewed and assigned to the PSRUC categories: benign, atypical urothelial cells (AUCs), suspicious for high-grade urothelial carcinoma (SHGUC), and high-grade urothelial carcinoma (HGUC). Original cytological diagnoses were recorded.

RESULTS

Fewer cases were given an AUC diagnosis using the PSRUC in comparison to the original diagnoses (26% vs 39%), while the association of AUCs with subsequent HGUC increased from 33% to 53% with the PSRUC. Using the PSRUC resulted in a higher number of low-grade carcinomas assigned to the benign (40%) rather than the AUC (22%) category. The performance of SHGUC/HGUC diagnoses was similar in both systems (predictive value = 94%).

CONCLUSIONS

The PSRUC seems to improve the performance of urine cytology by limiting the AUC category to cases that are more strongly associated with HGUC.

The cytomorphological features of low-grade urothelial neoplasms vary by specimen type

BACKGROUND

Urinary tract (UT) cytology has been used successfully to diagnose high-grade urothelial carcinoma but is reported to have poor sensitivity for low-grade urothelial neoplasms (LGUNs). However, the literature has shown that LGUN may be associated with atypical findings in UT specimens. The authors determined which features were most commonly observed, and whether the method of specimen procurement had an effect.

METHODS

A total of 326 specimens were identified over an 8-year period. One hundred fifty-three specimens were reviewed and graded for cellularity, number of tissue fragments (TFs), degeneration, inflammation, hyperchromasia, nuclear pleomorphism, nuclear border irregularity, nuclear size, cytoplasmic tails, nuclear eccentricity, and high-grade features.

RESULTS

Of the 153 specimens, 86 specimens (56.2%) demonstrated cellular atypia; of those, 51.2% were voided urine (VU) and 31.4% were UT washing (UW) specimens. The majority of specimens had many cells (46.5%), many single cells (44.2%), few to moderate TFs (46.5% and 27.9%, respectively), mild hyperchromasia (52.3%), mild nuclear pleomorphism (51.2%), mild nuclear border irregularity (60.5%), cytoplasmic tails (51.2%), and few to moderate eccentric nuclei (37.2% and 36.1%, respectively). The presence of TFs, cytoplasmic tails, and eccentric and enlarged nuclei were significantly more common in UW versus VU specimens (P = .036, .012, .014, and .027, respectively) and in UW versus benign UW controls (P = .001, .002, .002, and .003, respectively).

CONCLUSIONS

Approximately 50% of UT specimens with LGUN on follow-up demonstrated atypical features. Based on comparison with benign UW controls, TFs, cytoplasmic tails, nuclear eccentricity, and enlarged nuclei were more pronounced in neoplastic UW than VU specimens, suggesting that the method of urine specimen procurement affects the presence of certain low-grade features. Cancer Cytopathol 2016;124:552-64. © 2016 American Cancer Society.

Automated urinalysis with expert review for incidental identification of atypical urothelial cells: An anticipated bladder carcinoma diagnosis

BACKGROUND

The most common diagnostic technique for the detection of malignant/atypical urothelial cells (m/AUC) is urinary cytology (Ucytol). Urinary sediment (Used) examination, often prescribed for asymptomatic, healthy subjects, can incidentally identify suspicious/AUC (s/AUC) in routine daily practice.

METHODS

Unstained, unfixed and uncentrifuged urine samples were analyzed with an automated intelligent microscopy (AIM) system. From January 2010, any incidental identification of s/AUC through expert revision of unclassified cell images was reported, according to internal protocols, as an additional note on the patients' laboratory report. Patients' symptomatology or previous history was unknown to the pathologist. All referrals from January 2010 to December 2014, with the s/AUC note, were reviewed and cross-referenced with Ucytol and histology data from a central database.

RESULTS

Of the 162 patients identified with s/AUC (0.1/1000 samples), 84% (n=136) performed further Ucytol and/or histological examinations. The sensitivity of the identification of non-transitory AUC at Used was 87.5%. Positive histological examinations were 91.2% classified as high-grade urothelial carcinoma.

CONCLUSIONS

Routine Used examination, with an AIM and expert revision, can identify the presence of AUC in a clinical laboratory setting, and for some subjects, may anticipate bladder carcinoma diagnosis.

Atypical urothelial tissue fragments in noninstrumented voided urine specimens are associated with low but significantly higher rates of urothelial neoplasia than benign-appearing urothelial tissue fragments

BACKGROUND

The interpretation of urothelial tissue fragments (UTF) in voided urine (VU) specimens is controversial. If UTF contain cytomorphologically atypical cells, the diagnosis often becomes more challenging. The authors previously analyzed the outcome of patients with benign-appearing UTF in 274 noninstrumented VU specimens. In this retrospective study, noninstrumented VU specimens containing UTF with atypical cytomorphological features (AUTF) were evaluated and compared with the previous results.

METHODS

The Johns Hopkins Hospital electronic pathology database was searched for VU cases containing UTF over a 5-year period.

RESULTS

A total of 170 noninstrumented VU specimens containing AUTF were identified. Twenty-four specimens had subsequent or coincidental surgical pathology specimens with the following overall rates of neoplasia: high-grade urothelial carcinoma: 8.8% (15 specimens), low-grade urothelial neoplasia: 1.2% (2 specimens), and prostate carcinoma invading the bladder: 0.6% (1 specimen). A total of 49 specimens (28.8%) were diagnosed with urolithiasis on follow-up. Twenty-five cases had follow-up cytology specimens, all of which were negative for malignancy. Of 72 cases without histopathologic, radiologic, or cytopathologic follow-up, 62 (86.1%) had a mean clinical follow-up of 22.5 months and 10 cases did not have clinical follow-up.

CONCLUSIONS

The presence of AUTF in noninstrumented VU is associated with low rates of urothelial neoplasia but a statistically higher risk of urothelial neoplasia than the presence of BUTF (10.0% vs 4.4%; P<.05). In particular, the rate of high-grade urothelial carcinoma is significantly higher in noninstrumented VU specimens containing AUTF than those containing BUTF (8.8% vs 0.7%; P<.0001). In addition, urolithiasis is associated with AUTF in a substantial percentage of noninstrumented VU specimens.