Citations

The Dublin ISUP Consensus Conference covered the proceedings on the best practice recommendations on nonurachal glandular lesions of the urinary bladder, bladder diverticular cancers, and molecular features of bladder and urachal glandular lesions. The conference proceedings on urachal neoplasms (except for their molecular features) are published elsewhere. The rationale for convening this conference was the lack of structured and consented pathologic recommendations in these rare lesions. Consensus by participants was reached on the following statements: (1) intestinal metaplasia with dysplasia is considered to be a precursor to primary bladder adenocarcinoma; (2) dysplasia arising from cystitis glandularis should be reported in terms of focality (focal or nonfocal) and grade (low or high); (3) the term “adenocarcinoma” should only be used for carcinomas showing pure (nonurothelial) morphology and should not be used interchangeably in urothelial carcinoma with “glandular differentiation” because of the pathobiological differences and management implications; (4) the different histologic subtypes of bladder adenocarcinoma should be specified in the report; (5) immunohistochemistry has an ancillary role in the work up of bladder adenocarcinoma versus gastrointestinal or Müllerian-type adenocarcinomas; (6) lymphovascular invasion should be included as a parameter when reporting bladder adenocarcinoma; (7) representative or targeted sampling will be sufficient for bladder diverticulum resection specimens; and (8) molecular analysis in genomic profiling should be performed only in advanced or metastatic bladder and urachal adenocarcinomas for targetable therapy. This report on glandular (nonurachal) lesions of the bladder from the Dublin ISUP consensus conference will serve as a best practice recommendation and as a guide for future research on these relatively rare lesions.

This manuscript summarizes the first part of the proceedings of the 2023 Dublin ISUP Consensus Conference encompassing the best practice recommendations on the pathology of neoplasms of urachal origin. The rationale for convening this consensus conference was the lack of structured and consented histopathologic recommendations in these rare tumors. Consensus among the meeting participants (n=80) was reached on the following statements: (1) combination of gross, histologic, clinical and imaging findings with exclusion of secondary tumor metastasis are to be used in the diagnosis of urachal carcinoma; (2) the 2022 World Health Organization (WHO) separate criteria for the diagnosis of urachal adenocarcinoma and for nonglandular carcinoma should be applied; (3) specific elements are to be evaluated and recorded in the gross examination of resection specimens containing urachal tumors; (4) sampling considerations for resection specimens containing urachal tumors are advised; (5) participants are against using 5% or 10% cutoff for the extent of intraepithelial carcinoma in urachal mucinous cystic tumor of low malignant potential; (6) use of immunohistochemical markers for the differential diagnosis of urachal adenocarcinomas in transurethral resection (TUR) specimen is considered optional; (7) similar tumor classificatory (nosology) rules for carcinomas arising from bladder mucosa (eg, urothelial carcinoma, squamous cell carcinoma, and neuroendocrine carcinoma) should be applied for nonglandular urachal carcinomas; (8) a new staging approach other than the previously proposed systems should be designed for urachal carcinoma; (9) a system modifying the current Tumor-Node-Metastasis (TNM)/American Joint Committee on Cancer (AJCC) staging system for urinary bladder cancer is considered appropriate for a study in urachal carcinoma; and (10) several histologic elements are to be reported when diagnosing urachal carcinoma in TUR and resection specimens. This report from the Dublin ISUP consensus conference will serve as a practice recommendation for pathologists and as a guide for future standardized reporting protocols and research regarding urachal tumors. In addition, an international database for urachal cancers under the guidance of ISUP is being planned to be established to address pertinent issues in the pathology of urachal cancers.

The Genitourinary Pathology Society (GUPS) undertook a critical review of the recent advances in bladder cancer focusing on important topics of high interest for the practicing surgical pathologist and urologist. This review represents the second of 2 manuscripts ensuing from this effort. Herein, we address the effective reporting of bladder cancer, focusing particularly on newly published data since the last 2016 World Health Organization (WHO) classification. In addition, this review focuses on the importance of reporting bladder cancer with divergent differentiation and variant (subtypes of urothelial carcinoma) histologies and the potential impact on patient care. We provide new recommendations for reporting pT1 staging in diagnostic pathology. Furthermore, we explore molecular evolution and classification, emphasizing aspects that impact the understanding of important concepts relevant to reporting and management of patients.

The Genitourinary Pathology Society (GUPS) undertook a critical review of the recent advances in bladder neoplasia with a focus on issues relevant to the practicing surgical pathologist for the understanding and effective reporting of bladder cancer, emphasizing particularly on the newly accumulated evidence post-2016 World Health Organization (WHO) classification. The work is presented in 2 manuscripts. Here, in the first, we revisit the nomenclature and classification system used for grading flat and papillary urothelial lesions centering on clinical relevance, and on dilemmas related to application in routine reporting. As patients of noninvasive bladder cancer frequently undergo cystoscopy and biopsy in their typically prolonged clinical course and for surveillance of disease, we discuss morphologies presented in these scenarios which may not have readily applicable diagnostic terms in the WHO classification. The topic of inverted patterns in urothelial neoplasia, particularly when prominent or exclusive, and beyond inverted papilloma has not been addressed formally in the WHO classification. Herein we provide a through review and suggest guidelines for when and how to report such lesions. In promulgating these GUPS recommendations, we aim to provide clarity on the clinical application of these not so uncommon diagnostically challenging situations encountered in routine practice, while also importantly advocating consistent terminology which would inform future work.

AimsDespite efforts to standardise grading of prostate cancer, even among experts there is still a considerable variation in grading practices. In this study we describe the use of Pathology Imagebase, a novel reference image library, for setting an international standard in prostate cancer grading.Methods and resultsThe International Society of Urological Pathology (ISUP) recently launched a reference image database supervised by experts. A panel of 24 international experts in prostate pathology reviewed independently microphotographs of 90 cases of prostate needle biopsies with cancer. A linear weighted kappa of 0.67 (95% confidence interval = 0.62–0.72) and consensus was reached in 50 cases. The interobserver weighted kappa varied from 0.48 to 0.89. The highest level of agreement was seen for Gleason score (GS) 3 + 3 = 6 (ISUP grade 1), while higher grades and particularly GS 4 + 3 = 7 (ISUP grade 3) showed considerable disagreement. Once a two‐thirds majority was reached, images were moved automatically into a public database available for all ISUP members at www.isupweb.org. Non‐members are able to access a limited number of cases.ConclusionsIt is anticipated that the database will assist pathologists to calibrate their grading and, hence, decrease interobserver variability. It will also help to identify instances where definitions of grades need to be clarified.

AimsDespite efforts to standardize histopathology practice through the development of guidelines, the interpretation of morphology is still hampered by subjectivity. We here describe Pathology Imagebase, a novel mechanism for establishing an international standard for the interpretation of pathology specimens.Methods and resultsThe International Society of Urological Pathology (ISUP) established a reference image database through the input of experts in the field. Three panels were formed, one each for prostate, urinary bladder and renal pathology, consisting of 24 international experts. Each of the panel members uploaded microphotographs of cases into a non‐public database. The remaining 23 experts were asked to vote from a multiple‐choice menu. Prior to and while voting, panel members were unable to access the results of voting by the other experts. When a consensus level of at least two‐thirds or 16 votes was reached, cases were automatically transferred to the main database. Consensus was reached in a total of 287 cases across five projects on the grading of prostate, bladder and renal cancer and the classification of renal tumours and flat lesions of the bladder. The full database is available to all ISUP members at www.isupweb.org. Non‐members may access a selected number of cases.ConclusionsIt is anticipated that the database will assist pathologists in calibrating their grading, and will also promote consistency in the diagnosis of difficult cases.