[Rare tumors and tumor types of the urinary system in the 5th edition of the WHO classification 2022]. / Seltenere Tumoren und Tumortypen des ableitenden Harnsystems in der 5. Aufl. der WHO-Klassifikation 2022.

The 5th edition of the World Health Organization (WHO) classification of tumors of the urinary tract and male genital organs introduced both general and specific changes in structure, classification, and nomenclature. This also applies to rarer tumors and tumor subtypes of the urinary system. Knowledge of these changes is relevant for routine histopathological work. This article provides an overview of the main new features of the rarer tumors and tumor subtypes of the urinary system in the new edition of the WHO classification.

Cystic Features in Renal Epithelial Neoplasms and Their Increasing Clinical and Pathologic Significance.

Most cystic renal tumors after resection (Boniak IIF to IV cysts) have an indolent course despite the significantly higher proportion of malignant [ie, renal cell carcinoma (RCC)] diagnosis. Most cystic renal tumors have clear cell histology that include cystic clear cell RCC and multilocular cystic renal neoplasm of low malignant potential (MCNLMP). There is growing evidence to suggest that MCNLMP, cystic clear cell RCC, and noncystic clear cell RCC form a cystic-to-solid biological spectrum with MCNLMP representing the most indolent form and with cystic clear cell RCC behaving better than noncystic (solid) clear cell RCC. Extensively (>75%) cystic clear cell RCC also has an excellent outcome similar to MCNLMP stressing the need to reevaluate the histologic criteria that separate these 2 cystic clear cell tumors. Other tumors with clear cells that can be extensively cystic such as the recently reclassified noncancerous clear cell papillary renal tumor and the newly described MED15::TFE3 RCC also have indolent course and may mimic MCNLMP. Cystic features occur also in renal tumors with nonclear cell histology including tumors capable of metastasis such as acquired cystic disease-associated, tubulocystic, fumarate hydratase-deficient, and eosinophilic solid and cystic RCCs. Cystic imaging presentation of some renal tumors such as papillary RCC can be attributed in part to pseudocystic necrosis and hemorrhage. It is important to know that tubulocystic RCC may have a lower Bosniak class presentation that overlaps with benign renal cysts (Bosniak I to IIF) that are managed conservatively. This review highlights the cystic renal tumors with clear cell and nonclear cell morphologies including some novel RCC subtypes that may have cystic features. The presence of cystic features and their extent may aid in the classification and prognostication of renal neoplasms underscoring its increasing importance in the pathologic diagnosis and reporting of renal neoplasia.

NKX3.1 Expression in Non-Prostatic Tumors and Characterizing its Expression in Esophageal/Gastroesophageal Adenocarcinoma.

The NKX3.1 immunohistochemical stain is widely recognized as a highly sensitive and specific marker for prostate adenocarcinoma. Nevertheless, its expression has been documented in various nonprostatic tissues and malignancies. This review aims to provide an overview of NKX3.1 expression in diverse tumor types, with a specific focus on its aberrant expression in esophageal/gastroesophageal adenocarcinoma (E/GE-ADC). In our investigation, we explored the expression of NKX3.1 in a series of E/GE-ADC to shed light on its prevalence in this tumor category. A total of 50 samples, comprising primary and metastatic E/GE-ADC specimens from 34 patients, were subjected to immunohistochemical analysis. Stained sections were scored based on the intensity and distribution-categorized as negative, weak, moderate, or strong in either a focal or diffuse pattern. Strong staining corresponds to the intensity observed in normal prostate controls, while focal and diffuse staining denote <50% and ≥50% of tumor nuclei staining positive, respectively. Our semiquantitative scoring revealed that 6 (12%) of the primary and metastatic E/GE-ADC specimens exhibited variable positivity for NKX3.1. This finding suggests that E/GE-ADC can sporadically stain positive for NKX3.1, introducing potential challenges in definitively determining the primary site of origin in certain clinical scenarios. Along with a literature review of NKX3.1 expression in other tumor types, our study provides additional important information about the extent to which this immunostain can be seen in E/GE-ADCs, which, to our knowledge, has not been reported.

Glandular Lesions of the Urinary Bladder: Diagnostic and Molecular Updates.

Glandular lesions in the urinary tract or their associated pathologies can pose a diagnostic challenge. There is a variety of benign alterations and tumor types that need to be taken into account in differential diagnostic considerations. In recent times, efforts for better defining these alterations or lesions both on the histopathological and molecular levels have been undertaken. This article will provide an update on current diagnostic and molecular considerations of these lesions.

The Impact of Inherited Genetic Variation on DNA Methylation in Prostate Cancer and Benign Tissues of African American and European American Men.

BACKGROUND: American men of African ancestry (AA) have higher prostate cancer incidence and mortality rates compared with American men of European ancestry (EA). Differences in genetic susceptibility mechanisms may contribute to this disparity. METHODS: To gain insights into the regulatory mechanisms of prostate cancer susceptibility variants, we tested the association between SNPs and DNA methylation (DNAm) at nearby CpG sites across the genome in benign and cancer prostate tissue from 74 AA and 74 EA men. Genome-wide SNP data (from benign tissue) and DNAm were generated using Illumina arrays. RESULTS: Among AA men, we identified 6,298 and 2,641 cis-methylation QTLs (meQTL; FDR of 0.05) in benign and tumor tissue, respectively, with 6,960 and 1,700 detected in EA men. We leveraged genome-wide association study (GWAS) summary statistics to identify previously reported prostate cancer GWAS signals likely to share a common causal variant with a detected meQTL. We identified nine GWAS-meQTL pairs with strong evidence of colocalization (four in EA benign, three in EA tumor, two in AA benign, and three in AA tumor). Among these colocalized GWAS-meQTL pairs, we identified colocalizing expression quantitative trait loci (eQTL) impacting four eGenes with known roles in tumorigenesis. CONCLUSIONS: These findings highlight epigenetic regulatory mechanisms by which prostate cancer-risk SNPs can modify local DNAm and/or gene expression in prostate tissue. IMPACT: Overall, our findings showed general consistency in the meQTL landscape of AA and EA men, but meQTLs often differ by tissue type (normal vs. cancer). Ancestry-based linkage disequilibrium differences and lack of AA representation in GWAS decrease statistical power to detect colocalization for some regions.

International Society of Urological Pathology (ISUP) Consensus Conference on Current Issues in Bladder Cancer. Working Group 2: Grading of Mixed Grade, Invasive Urothelial Carcinoma Including Histologic Subtypes and Divergent Differentiations, and Non-Urothelial Carcinomas.

The 2022 International Society of Urological Pathology (ISUP) Consensus Conference on Urinary Bladder Cancer Working Group 2 was tasked to provide evidence-based proposals on the applications of grading in noninvasive urothelial carcinoma with mixed grades, invasive urothelial carcinoma including subtypes (variants) and divergent differentiations, and in pure non-urothelial carcinomas. Studies suggested that predominantly low-grade noninvasive papillary urothelial carcinoma with focal high-grade component has intermediate outcome between low- and high-grade tumors. However, no consensus was reached on how to define a focal high-grade component. By 2004 WHO grading, the vast majority of lamina propria-invasive (T1) urothelial carcinomas are high-grade, and the rare invasive low-grade tumors show only limited superficial invasion. While by 1973 WHO grading, the vast majority of T1 urothelial carcinomas are G2 and G3 and show significant differences in outcome based on tumor grade. No consensus was reached if T1 tumors should be graded either by the 2004 WHO system or by the 1973 WHO system. Because of the concern for underdiagnosis and underreporting with potential undertreatment, participants unanimously recommended that the presence of urothelial carcinoma subtypes and divergent differentiations should be reported. There was consensus that the extent of these subtypes and divergent differentiations should also be documented in biopsy, transurethral resection, and cystectomy specimens. Any distinct subtype and divergent differentiation should be diagnosed without a threshold cutoff, and each type should be enumerated in tumors with combined morphologies. The participants agreed that all subtypes and divergent differentiations should be considered high-grade according to the 2004 WHO grading system. However, participants strongly acknowledged that subtypes and divergent differentiations should not be considered as a homogenous group in terms of behavior. Thus, future studies should focus on individual subtypes and divergent differentiations rather than lumping these different entities into a single clinicopathological group. Likewise, clinical recommendations should pay attention to the potential heterogeneity of subtypes and divergent differentiations in terms of behavior and response to therapy. There was consensus that invasive pure squamous cell carcinoma and pure adenocarcinoma of the bladder should be graded according to the degree of differentiation. In conclusion, this summary of the International Society of Urological Pathology Working Group 2 proceedings addresses some of the issues on grading beyond its traditional application, including for papillary urothelial carcinomas with mixed grades and with invasive components. Reporting of subtypes and divergent differentiation is also addressed in detail, acknowledging their role in risk stratification. This report could serve as a guide for best practices and may advise future research and proposals on the prognostication of these tumors.

The influence of the "cancer" label on perceptions and management decisions for low-grade prostate cancer.

BACKGROUND: Grade Group 1 (GG1) prostate cancer should be managed with active surveillance (AS). Global uptake of AS remains disappointingly slow and heterogeneous. Removal of cancer labels has been proposed to reduce GG1 overtreatment. We sought to determine the impact of GG1 disease terminology on individual's perceptions and decision making. METHODS: Discrete choice experiments were conducted on 3 cohorts: healthy men, canonical partners (partners), and patients with GG1 (patients). Participants reported preferences in a series of vignettes with 2 scenarios each, permuting key opinion leader-endorsed descriptors: biopsy (adenocarcinoma, acinar neoplasm, prostatic acinar neoplasm of low malignant potential [PAN-LMP], prostatic acinar neoplasm of uncertain malignant potential), disease (cancer, neoplasm, tumor, growth), management decision (treatment, AS), and recurrence risk (6%, 3%, 1%, <1%). Influence on scenario selection were estimated by conditional logit models and marginal rates of substitution. Two additional validation vignettes with scenarios portraying identical descriptors except the management options were embedded into the discrete choice experiments. RESULTS: Across cohorts (194 healthy men, 159 partners, and 159 patients), noncancer labels PAN-LMP or prostatic acinar neoplasm of uncertain malignant potential and neoplasm, tumor, or growth were favored over adenocarcinoma and cancer (P < .01), respectively. Switching adenocarcinoma and cancer labels to PAN-LMP and growth, respectively, increased AS choice by up to 17%: healthy men (15%, 95% confidence interval [CI] = 10% to 20%, from 76% to 91%, P < .001), partners (17%, 95% CI = 12% to 24%, from 65% to 82%, P < .001), and patients (7%, 95% CI = 4% to 12%, from 75% to 82%, P = .063). The main limitation is the theoretical nature of questions perhaps leading to less realistic choices. CONCLUSIONS: "Cancer" labels negatively affect perceptions and decision making regarding GG1. Relabeling (ie, avoiding word "cancer") increases proclivity for AS and would likely improve public health.

Physician Perception of Grade Group 1 Prostate Cancer.

BACKGROUND: Despite its low-risk nature, grade group 1 (GG 1) prostate cancer (PCa) remains overtreated. This suggests a disconnect between daily physician practice and the standard of care. We hypothesized that GG 1 disease is overtreated because of common misconceptions regarding its true natural history. OBJECTIVE: To survey physicians worldwide to better understand their approach to management of GG 1 PCa. DESIGN, SETTING, AND PARTICIPANTS: A 17-question survey was sent to urology, radiation oncology, and pathology societies on six continents, and was posted on Twitter. Responses were collected and analyzed. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Pearson's χ2 test was used to assess correlation between physician-related variables and the perception of active surveillance (AS) for GG 1 PCa. Logistic regression was used for multivariable analysis. Statistical analysis was performed using SPSS version 21. RESULTS AND LIMITATIONS: Among 1303 participants, 55% were urologists, 47% had completed fellowship, and 49% practice in an academic setting. Among the clinicians, 724 (83%) routinely recommend AS for GG 1 PCa and have never/rarely regretted it, while 18 (2%) "often" regretted it. Routine AS was more common among physicians aged <40 yr, those in practice for <10 yr, and those living in North America, Europe, or Australia/New Zealand. More than one-third of the respondents practicing in nonacademic settings reported 15-yr PCa mortality in low-risk PCa of >3%. Regarding reclassification of GG 1 to a precancerous lesion, 428 (39%) felt that this is a good idea, 340 (31%) disagreed, and 323 (30%) were uncertain. Those in support were more likely to be aged <40 yr (p = 0.001), in practice for <5 yr (p = 0.005), urologists (p < 0.001), and fellows trained in urologic oncology (p < 0.001). Opposition was common among pathologists (61%). Among terminologies proposed to replace "cancer" for GG 1 are neoplasm of low malignant potential (51% approval), indolent neoplasm rarely requiring treatment (23%), and indolent lesion of epithelial origin (8%). CONCLUSIONS: AS is more commonly recommended by physicians who are younger, are fellowship-trained in urologic oncology, practice in academic settings, and are based in North America, Europe, or Australia/New Zealand. Misconceptions regarding AS outcomes may hinder its adoption. Frequent use of AS is associated with support for changing the "cancer" nomenclature. PATIENT SUMMARY: In this study, we found that active surveillance remains underused in the management of low-risk prostate cancer because of incorrect perceptions regarding cancer outcomes. Omitting the word "cancer" for low-risk lesions is a challenging but promising effort that is favored by many clinicians, particularly by those who advocate for active surveillance.

Renaming Grade Group 1 Prostate "Cancer" From a Pathology Perspective: A Call for Multidisciplinary Discussion.

Despite the innovations made to enhance smarter screening and conservative management for low-grade prostate cancer, overdiagnosis, and overtreatment remains a major health care problem. Driven by the primary goal of reducing harm to the patients, relabeling of nonlethal grade group 1 (GG 1) prostate cancer has been proposed but faced varying degrees of support and objection from clinicians and pathologists. GG 1 tumor exhibits histologic (invasive) and molecular features of cancer but paradoxically, if pure, is unable to metastasize, rarely extends out of the prostate, and if resected, has a cancer-specific survival approaching 100%. Most of the arguments against relabeling GG 1 relate to concerns of missing a higher-grade component through the unsampled area at biopsy. However, the designation of tumor benignity or malignancy should not be based on the shortcomings of a diagnostic procedure and sampling errors. This review explores possible solutions, mainly the feasibility of renaming GG 1 in radical prostatectomy (RP) with ramifications in biopsy diagnosis, acceptable for both pathologists and clinicians. One workable approach is to rename GG 1 in RP with a cautious neutral or nonbenign non-cancer term (eg, acinar neoplasm) using "defined criteria" that will stop the indiscriminate reporting of every GG 1 in biopsy as carcinoma including eventual insignificant microtumors in RPs. Use of a corresponding noncommittal term at biopsy while commenting on the possibility of an undersampled nonindolent cancer, might reduce the pathologist's concerns about upgrading. Dropping the word "carcinoma" in biopsy preempts the negative consequences of labeling the patient with cancer, including unnecessary definitive therapy (the root cause of overtreatment). Renaming should retain the status quo of contemporary grading and risk stratifications for management algorithms while trying to minimize overtreatment. However, the optimal approach to find answers to this issue is through multidisciplinary discussions of key stakeholders with a specific focus on patient-centered concerns and their ramifications in our practices. GG 1 renaming has been brought up in the past and came up again despite the continued counterarguments, and if not addressed more comprehensively will likely continue to reemerge as overdiagnosis, overtreatment, and patient's sufferings persist.

Blood Prostate-specific Antigen by Volume of Benign, Gleason Pattern 3 and 4 Prostate Tissue.

OBJECTIVE: To evaluate how blood levels of prostate-specific antigen (PSA) relate to prostate volume of benign tissue, Gleason pattern 3 (GP3) and Gleason pattern 4 (GP4) cancer. METHODS: The cohort included 2209 consecutive men undergoing radical prostatectomy at 2 academic institutions with pT2N0, Grade Group 1-4 prostate cancer and an undetectable postoperative PSA. Volume of benign, GP3, and GP4 were estimated. The primary analysis evaluated the association between PSA and volume of each type of tissue using multivariable linear regression. R2, a measure of explained variation, was calculated using a multivariable model. RESULTS: Estimated contribution to PSA was 0.04/0.06 ng/mL/cc for benign, 0.08/0.14 ng/mL/cc for GP3, and 0.62/0.80 ng/ml/cc for GP4 for the 2 independent cohorts, respectively. GP4 was associated with 6 to 8-fold more PSA per cc compared to GP3 and 15-fold higher compared to benign tissue. We did not observe a difference between PSA per cc for GP3 vs. benign tissue (P = 0.2). R2 decreased only slightly when removing age (0.006/0.018), volume of benign tissue (0.051/0.054) or GP3 (0.014/0.023) from the model. When GP4 was removed, R2 decreased 0.051/0.310. PSA density (PSA divided by prostate volume) was associated with volume of GP4 but not GP3, after adjustment for benign volume. CONCLUSION: Gleason pattern 4 cancer contributes considerably more to PSA and PSA density per unit volume compared to GP3 and benign tissue. Contributions from GP3 and benign are similar. Further research should examine the utility of determining clinical management recommendations by absolute volume of GP4 rather than the ratio of GP3 to GP4.

Flat intraurothelial lesions of the urinary bladder-do hyperplasia, dysplasia, and atypia of unknown significance need to exist as diagnostic entities? and how to handle in routine clinical practice.

Classification of the putative flat preneoplastic and neoplastic lesions of the urothelium with features subthreshold for urothelial carcinoma in situ remains a challenging, indeed, vexing problem in diagnostic surgical pathology. This area, subtending lesions including flat urothelial hyperplasia, urothelial dysplasia, and atypia of unknown significance, has struggled under evolving classifications, changing criteria, and limited clinical actionability, all confounded by the recognized lack of diagnostic reproducibility. Herein, we review the state of the literature around these lesions, reviewing contemporary criteria and definitions, assessing the arguments in favor and against of retaining hyperplasia, dysplasia, and atypia of unknown significance as diagnostic entities. We clarify the intent of the original definitions for dysplasia as a lesion felt to be clearly neoplastic but with morphologic features that fall short of the threshold of urothelial carcinoma in situ. While several pathologists, including some experts in the field, conflate the term dysplasia with urothelial atypia of unknown significance, the latter is defined as a descriptive diagnosis term to express diagnostic uncertainty of a lesion of whether it is clearly reactive or neoplastic. Both molecular studies and clinical needs are considered, as we outline our approach on diagnosing each of these lesions in clinical practice. Recommendations are made to guide consistency and interoperability in future scholarship, and the place of these lesions in context of evolving trends in the field is considered.

Updates in Grading of Renal Cell Carcinomas Beyond Clear Cell Renal Cell Carcinoma and Papillary Renal Cell Carcinoma.

The World Health Organization (WHO) recommends grading of clear cell renal cell carcinoma (RCC) and papillary RCC using the WHO/International Society of Urological Pathology (ISUP) grade, which is primarily based on nuclear features. As the spectrum of RCC continues to evolve, with more recently described subtypes in the past decade, literature evidence on grading these subtypes is limited or not available for some tumor types. Herein, we outline a pragmatic approach to the topic of grading RCC, dividing the contemporarily described RCC subtypes into 7 categories based on the potential clinical applicability of grading as a useful prognostic parameter: (1) RCC subtypes that are reasonably validated and recommended for WHO/ISUP grading; (2) RCC subtypes where WHO/ISUP is not applicable; (3) RCC subtypes where WHO/ISUP grading is potentially clinically useful; (4) inherently aggressive RCC subtypes where histologic classification itself confers an aggressive biologic potential; (5) renal epithelial tumors where WHO/ISUP grading provides potentially misleading prognostic implication; (6) renal epithelial neoplasms where low WHO/ISUP grade features are a prerequisite for accurate histologic classification; and (7) renal epithelial neoplasms with no or limited data on grading or incomplete understanding of the biologic potential. Our aim in outlining this approach is 2-fold: (a) identify the gaps in understanding and application of grading in RCC subtypes so that researchers in the field may perform additional studies on the basis of which the important pathologic function of assignment of grade may be recommended to be performed as a meaningful exercise across a wider spectrum of RCC; and (b) to provide guidance in the interim to surgical pathologists in terms of providing clinically useful grading information in RCC based on currently available clinicopathologic information.

SOX2 mediates metabolic reprogramming of prostate cancer cells.

New strategies are needed to predict and overcome metastatic progression and therapy resistance in prostate cancer. One potential clinical target is the stem cell transcription factor SOX2, which has a critical role in prostate development and cancer. We thus investigated the impact of SOX2 expression on patient outcomes and its function within prostate cancer cells. Analyses of SOX2 expression among a case-control cohort of 1028 annotated tumor specimens demonstrated that SOX2 expression confers a more rapid time to metastasis and decreased patient survival after biochemical recurrence. SOX2 ChIP-Seq analyses revealed SOX2-binding sites within prostate cancer cells which differ significantly from canonical embryonic SOX2 gene targets, and prostate-specific SOX2 gene targets are associated with multiple oncogenic pathways. Interestingly, phenotypic and gene expression analyses after CRISPR-mediated deletion of SOX2 in castration-resistant prostate cancer cells, as well as ectopic SOX2 expression in androgen-sensitive prostate cancer cells, demonstrated that SOX2 promotes changes in multiple metabolic pathways and metabolites. SOX2 expression in prostate cancer cell lines confers increased glycolysis and glycolytic capacity, as well as increased basal and maximal oxidative respiration and increased spare respiratory capacity. Further, SOX2 expression was associated with increased quantities of mitochondria, and metabolomic analyses revealed SOX2-associated changes in the metabolism of purines, pyrimidines, amino acids and sugars, and the pentose phosphate pathway. Analyses of SOX2 gene targets with central functions metabolism (CERK, ECHS1, HS6SDT1, LPCAT4, PFKP, SLC16A3, SLC46A1, and TST) document significant expression correlation with SOX2 among RNA-Seq datasets derived from patient tumors and metastases. These data support a key role for SOX2 in metabolic reprogramming of prostate cancer cells and reveal new mechanisms to understand how SOX2 enables metastatic progression, lineage plasticity, and therapy resistance. Further, our data suggest clinical opportunities to exploit SOX2 as a biomarker for staging and imaging, as well as a potential pharmacologic target.

Spectrum of biphasic renal cell carcinomas with hyalinized stroma and psammoma bodies associated and not associated with NF2 alteration.

A unique subtype of biphasic renal cell carcinoma (RCC) was recently described and termed biphasic hyalinizing psammomatous RCC (BHPRCC). This tumor shows a dual population of larger cells and small cells surrounding basement membrane-like materials and invariably has papillary features, hyalinized stroma, and psammoma calcifications. The biphasic pattern in BHPRCC may resemble that of RCC associated with TFEB gene fusion or t (6;11) RCC. However, all reported BHPRCCs had no TFEB alterations and all were associated with neurofibromin 2 (NF2) mutations. Herein, we present three biphasic RCCs encompassing the reported BHPRCC morphologies. One RCC showed solid, nested, papillary, and tubular growths, with biphasic pattern of larger cells surrounding clusters of smaller cells arranged around basement membrane-like materials, and harbored NF2 mutation consistent with BHPRCC. This patient developed bone metastasis 59 months after surgery. The two other biphasic RCCs showed morphologic overlap to BHPRCC, but in addition had other features not seen in BHPRCC, such as lack of papillary pattern, having large tubules containing mucinous to collagenous spherules (mucicarmine and collagen IV positive) bordered by a single layer of small cells with occasional central targetoid psammoma bodies, and with widespread nuclear grooves. Interestingly, these two tumors also did not show alterations in NF2 or TFEB including translocation or amplification. In conclusion, we report another example of the novel BHPRCC that had metastasized and two biphasic RCCs not associated with NF2 or TFEB alterations; the latter two shared additional distinct morphological features and may represent a unique biphasic RCC distinct from the novel BHPRCC.

Histological validation of prostate tissue composition measurement using hybrid multi-dimensional MRI: agreement with pathologists' measures.

PURPOSE: To validate prostate tissue composition measured using hybrid multi-dimensional MRI (HM-MRI) by comparing with reference standard (ground truth) results from pathologists' interpretation of clinical histopathology slides following whole mount prostatectomy. MATERIALS AND METHODS: 36 prospective participants with biopsy-confirmed prostate cancer underwent 3 T MRI prior to radical prostatectomy. Axial HM-MRI was acquired with all combinations of echo times of 57, 70, 150, 200 ms and b-values of 0, 150, 750, 1500 s/mm2 and data were fitted using a 3-compartment signal model using custom software to generate volumes for each tissue component (stroma, epithelium, lumen). Three experienced genitourinary pathologists independently as well as in consensus reviewed each histology image and provide an estimate of percentage of epithelium and lumen for regions-of-interest corresponding to MRI (n = 165; 64 prostate cancers and 101 benign tissue). Agreement statistics using total deviation index (TDI0.9) was performed for tissue composition measured using HM-MRI and reference standard results from pathologists' consensus. RESULTS: Based on the initial results showing typical variation among pathologists TDI0.9 = 25%, we determined we will declare acceptable agreement if the 95% one-sided upper confident limit of TDI0.9 is less than 30%. The results of tissue composition measurement from HM-MRI compared to ground truth results from the consensus of 3 pathologists, reveal that ninety percent of absolute paired differences (TDI0.9) were within 18.8% and 22.4% in measuring epithelium and lumen, respectively. We are 95% confident that 90% of absolute paired differences were within 20.6% and 24.2% in measuring epithelium and lumen, respectively. These were less than our criterion of 30% and inter-pathologists' agreement (22.3% for epithelium and 24.2% for lumen) and therefore we accept the agreement performance of HM-MRI. The results revealed excellent area under the ROC curve for differentiating cancer from benign tissue based on epithelium (HM-MRI: 0.87, pathologists: 0.97) and lumen volume (HM-MRI: 0.85, pathologists: 0.77). CONCLUSION: The agreement in tissue composition measurement using hybrid multidimensional MRI and consensus of pathologists is on par with the inter-raters (pathologists) agreement.