What's new in WHO fifth edition - urinary tract.

The fifth edition of the WHO Blue Book on urological tumours, specifically in the bladder chapter, represents a refinement and update in the classification of bladder tumours building on the aggregate major changes made in previous editions. Progress in the molecular underpinnings of urothelial tumours, particularly with promising stratifiers for more precision-based treatment approaches, have been made. Special attention has been paid to burning questions in bladder pathology, such as grading, heterogeneous lesions, inverted tumours and substaging. The concept of neuroendocrine tumours will be explained precisely.

Identification of areas of grading difficulties in prostate cancer and comparison with artificial intelligence assisted grading.

The International Society of Urological Pathology (ISUP) hosts a reference image database supervised by experts with the purpose of establishing an international standard in prostate cancer grading. Here, we aimed to identify areas of grading difficulties and compare the results with those obtained from an artificial intelligence system trained in grading. In a series of 87 needle biopsies of cancers selected to include problematic cases, experts failed to reach a 2/3 consensus in 41.4% (36/87). Among consensus and non-consensus cases, the weighted kappa was 0.77 (range 0.68-0.84) and 0.50 (range 0.40-0.57), respectively. Among the non-consensus cases, four main causes of disagreement were identified: the distinction between Gleason score 3 + 3 with tangential cutting artifacts vs. Gleason score 3 + 4 with poorly formed or fused glands (13 cases), Gleason score 3 + 4 vs. 4 + 3 (7 cases), Gleason score 4 + 3 vs. 4 + 4 (8 cases) and the identification of a small component of Gleason pattern 5 (6 cases). The AI system obtained a weighted kappa value of 0.53 among the non-consensus cases, placing it as the observer with the sixth best reproducibility out of a total of 24. AI may serve as a decision support and decrease inter-observer variability by its ability to make consistent decisions. The grading of these cancer patterns that best predicts outcome and guides treatment warrants further clinical and genetic studies. Results of such investigations should be used to improve calibration of AI systems.

Tumor microenvironment defines the invasive phenotype of AIP-mutation-positive pituitary tumors.

The molecular mechanisms leading to aryl hydrocarbon receptor interacting protein (AIP) mutation-induced aggressive, young-onset growth hormone-secreting pituitary tumors are not fully understood. In this study, we have identified that AIP-mutation-positive tumors are infiltrated by a large number of macrophages compared to sporadic tumors. Tissue from pituitary-specific Aip-knockout (AipFlox/Flox;Hesx1Cre/+) mice recapitulated this phenotype. Our human pituitary tumor transcriptome data revealed the "epithelial-to-mesenchymal transition (EMT) pathway" as one of the most significantly altered pathways in AIPpos tumors. Our in vitro data suggest that bone marrow-derived macrophage-conditioned media induces more prominent EMT-like phenotype and enhanced migratory and invasive properties in Aip-knockdown somatomammotroph cells compared to non-targeting controls. We identified that tumor-derived cytokine CCL5 is upregulated in AIP-mutation-positive human adenomas. Aip-knockdown GH3 cell-conditioned media increases macrophage migration, which is inhibited by the CCL5/CCR5 antagonist maraviroc. Our results suggest that a crosstalk between the tumor and its microenvironment plays a key role in the invasive nature of AIP-mutation-positive tumors and the CCL5/CCR5 pathway is a novel potential therapeutic target.

Datasets for the reporting of neoplasia of the testis: recommendations from the International Collaboration on Cancer Reporting.

We here describe the development of an evidence-based cancer dataset by an International Collaboration on Cancer Reporting expert panel for the reporting of primary testicular neoplasia, and present the 'required' and 'recommended' elements to be included in the pathology report, as well as a commentary. This dataset encompasses the updated 2016 World Health Organisation classification of urological tumours, the results of an International Society of Urological Pathology consultation, and also staging with our preferred method: the American Joint Committee on Cancer version 8. Implementation of this dataset will facilitate consistent and accurate data collection between different cohorts, facilitate research, and hopefully result in improved patient management.

Sequencing of prostate cancers identifies new cancer genes, routes of progression and drug targets.

Prostate cancer represents a substantial clinical challenge because it is difficult to predict outcome and advanced disease is often fatal. We sequenced the whole genomes of 112 primary and metastatic prostate cancer samples. From joint analysis of these cancers with those from previous studies (930 cancers in total), we found evidence for 22 previously unidentified putative driver genes harboring coding mutations, as well as evidence for NEAT1 and FOXA1 acting as drivers through noncoding mutations. Through the temporal dissection of aberrations, we identified driver mutations specifically associated with steps in the progression of prostate cancer, establishing, for example, loss of CHD1 and BRCA2 as early events in cancer development of ETS fusion-negative cancers. Computational chemogenomic (canSAR) analysis of prostate cancer mutations identified 11 targets of approved drugs, 7 targets of investigational drugs, and 62 targets of compounds that may be active and should be considered candidates for future clinical trials.

Gleason grade 4 prostate adenocarcinoma patterns: an interobserver agreement study among genitourinary pathologists.

AIMS: To assess the interobserver reproducibility of individual Gleason grade 4 growth patterns. METHODS AND RESULTS: Twenty-three genitourinary pathologists participated in the evaluation of 60 selected high-magnification photographs. The selection included 10 cases of Gleason grade 3, 40 of Gleason grade 4 (10 per growth pattern), and 10 of Gleason grade 5. Participants were asked to select a single predominant Gleason grade per case (3, 4, or 5), and to indicate the predominant Gleason grade 4 growth pattern, if present. 'Consensus' was defined as at least 80% agreement, and 'favoured' as 60-80% agreement. Consensus on Gleason grading was reached in 47 of 60 (78%) cases, 35 of which were assigned to grade 4. In the 13 non-consensus cases, ill-formed (6/13, 46%) and fused (7/13, 54%) patterns were involved in the disagreement. Among the 20 cases where at least one pathologist assigned the ill-formed growth pattern, none (0%, 0/20) reached consensus. Consensus for fused, cribriform and glomeruloid glands was reached in 2%, 23% and 38% of cases, respectively. In nine of 35 (26%) consensus Gleason grade 4 cases, participants disagreed on the growth pattern. Six of these were characterized by large epithelial proliferations with delicate intervening fibrovascular cores, which were alternatively given the designation fused or cribriform growth pattern ('complex fused'). CONCLUSIONS: Consensus on Gleason grade 4 growth pattern was predominantly reached on cribriform and glomeruloid patterns, but rarely on ill-formed and fused glands. The complex fused glands seem to constitute a borderline pattern of unknown prognostic significance on which a consensus could not be reached.

Endonasal endoscopic transsphenoidal pituitary surgery: early experience and outcome in paediatric Cushing's disease.

BACKGROUND: Selective adenomectomy remains the first-line treatment for Cushing's disease (CD), until recently by microscopic transsphenoidal pituitary surgery. Endonasal transsphenoidal endoscopic surgery (ETES) is emerging as a novel, less invasive treatment for pituitary adenomas and has become the optimal surgical approach. OBJECTIVE: There are no published series for the treatment of paediatric CD by ETES, and we report our centre's preliminary results. DESIGN: Retrospective analysis. PATIENTS: Six paediatric patients (median age 15·8 years; range 11·7-17·0 years) fulfilled standard diagnostic criteria for CD. Preoperatively, no abnormality was identified on pituitary MR scanning in 3 (50%) patients, one had a macroadenoma. Bilateral petrosal sinus sampling demonstrated central ACTH secretion (IPS/P ACTH ratio ≥3·0, post-CRH) in 3/6 (50%) patients. The same neurosurgeon and endoscopic nasal surgeon undertook all the operations. OUTCOME MEASURES: Therapeutic outcome and rate of complications. RESULTS: Clinical recovery and biochemical 'cure' were achieved in 5 (83%) patients, and a corticotroph adenoma was confirmed histologically in all cured cases. One case developed post-operative CSF leak requiring lumbar drain insertion and patching. At a mean interval of 4·7 years (0·1-10·8 years) post-operatively, cured patients have shown no recurrence. One patient, with a large diffuse adenoma requiring more extensive surgery, has panhypopituitarism, and another patient has GH and gonadotrophin deficiencies. CONCLUSIONS: Our experience shows that ETES for removing corticotroph adenomas in children, in most cases not visualized on MRI, is minimally invasive and gave excellent post-operative recovery/results. In skilled hands, this technique provides an alternative to conventional transsphenoidal microscopic surgery in managing paediatric CD.

Oncogene-induced senescence in pituitary adenomas and carcinomas.

OBJECTIVE: The model of "oncogene-induced senescence" (OIS), resulting in cell-proliferation arrest, has recently been suggested as a possible explanation for the non-progression of pituitary tumours to malignancy. The aim of the study was to compare the expression of ß-galactosidase as a molecular marker of OIS, and p21/p16 as additional markers involved in mediating OIS, in pituitary adenomas, carcinomas and normal pituitary tissue. DESIGN: We performed: a) semi-quantitative immunohistochemistry (ß-galactosidase, p16, p21) in 41 pituitary adenomas [(11 GH-secreting, 9 PRL-secreting, 10 ACTH-secreting, 11 non-functioning (NFPAs)], 6 carcinomas (3 multihormonal: PRL/ACTH/GH, PRL/ACTH, PRL/GH/FSH; 1 non-functioning; 2 ACTH-secreting) and 7 normal pituitary tissues; b) quantitative PCR of mRNA (p16 and p21) in 6 GH-secreting, 6 NFPAs and 6 normal pituitary tissues. RESULTS: ß-galactosidase was significantly increased in GH-secreting tumours (P=0.002), NFPAs (P=0.04), macroadenomas (P=0.03) and carcinomas (P=0.02), as compared to normal pituitary tissue. We found that p16 expression was significantly lower in all tumours (both adenomas and carcinomas) probably secondary to reduced transcription, at least for NFPAs; p21 showed a different biological behaviour, implying that p21 and p16 may play different roles in the senescence of each individual type of adenoma. CONCLUSIONS: ß-galactosidase was significantly over-expressed in GH-secreting and NFPAs, and unexpectedly also in carcinomas. We speculate that the senescence pathway, which may explain the rarity of malignant progression to carcinomas in GH-secreting and NFPAs, might not be universal but cell-type specific.

Measuring interobserver variation in a pathology EQA scheme using weighted κ for multiple readers.

BACKGROUND: A Urological Pathology External Quality Assurance (EQA) Scheme in the UK has reported observer variation in the diagnosis and grading of adenocarcinoma in prostatic biopsies using basic κ statistics, which rate all disagreements equally. AIM: The aim of this study is to use customised weighting schemes to report κ statistics that reflect the closeness of interobserver agreement in the prostate EQA scheme. METHODS: A total of 83, 114 and 116 pathologists took part, respectively, in three web-based circulations and were classified as either expert or other readers. For analyses of diagnosis, there were 10, 8 and 8 cases in the three circulations, respectively. For analyses of Gleason Sum Score, only invasive cases were included, leaving 5, 5 and 6 cases, respectively. Analyses were conducted using customised weighting schemes with 'pairwise-weighted' κ for multiple readers. RESULTS: Analysis of diagnosis for all circulations and all readers gave a composite κ value of 0.86 and pairwise-weighted κ (κ(p-w)) value of 0.91, both regarded as 'almost perfect' agreement. This was due to the high proportion of responses that showed partial agreement. Analysis of Gleason Sum Score gave κ=0.38 and κ(p-w)=0.58 over all circulations and all readers, indicating that discrepancies occur at the boundary between adjacent grades and may not be as clinically significant as suggested by composite κ. CONCLUSION: Weighted κ show higher levels of agreement than previously reported as they have the advantage of applying weighting, which reflects the relative importance of different types of discordance in diagnosis or grading. Agreement on grading remained low.

A practical application of analysing weighted kappa for panels of experts and EQA schemes in pathology.

BACKGROUND: Kappa statistics are frequently used to analyse observer agreement for panels of experts and External Quality Assurance (EQA) schemes and generally treat all disagreements as total disagreement. However, the differences between ordered categories may not be of equal importance (eg, the difference between grades 1 vs 2 compared with 1 vs 3). Weighted kappa can be used to adjust for this when comparing a small number of readers, but this has not as yet been applied to the large number of readers typical of a national EQA scheme. AIM: To develop and validate a method for applying weighted kappa to a large number of readers within the context of a real dataset: the UK National Urological Pathology EQA Scheme for prostatic biopsies. METHODS: Data on Gleason grade recorded by 19 expert readers were extracted from the fixed text responses of 20 cancer cases from four circulations of the EQA scheme. Composite kappa, currently used to compute an unweighted kappa for large numbers of readers, was compared with the mean kappa for all pairwise combinations of readers. Weighted kappa generalised for multiple readers was compared with the newly developed 'pairwise-weighted' kappa. RESULTS: For unweighted analyses, the median increase from composite to pairwise kappa was 0.006 (range -0.005 to +0.052). The difference between the pairwise-weighted kappa and generalised weighted kappa for multiple readers never exceeded ±0.01. CONCLUSION: Pairwise-weighted kappa is a suitable and highly accurate approximation to weighted kappa for multiple readers.

The role of the aryl hydrocarbon receptor-interacting protein gene in familial and sporadic pituitary adenomas.

CONTEXT: Mutations have been identified in the aryl hydrocarbon receptor-interacting protein (AIP) gene in familial isolated pituitary adenomas (FIPA). It is not clear, however, how this molecular chaperone is involved in tumorigenesis. OBJECTIVE: AIP sequence changes and expression were studied in FIPA and sporadic adenomas. The function of normal and mutated AIP molecules was studied on cell proliferation and protein-protein interaction. Cellular and ultrastructural AIP localization was determined in pituitary cells. PATIENTS: Twenty-six FIPA kindreds and 85 sporadic pituitary adenoma patients were included in the study. RESULTS: Nine families harbored AIP mutations. Overexpression of wild-type AIP in TIG3 and HEK293 human fibroblast and GH3 pituitary cell lines dramatically reduced cell proliferation, whereas mutant AIP lost this ability. All the mutations led to a disruption of the protein-protein interaction between AIP and phosphodiesterase-4A5. In normal pituitary, AIP colocalizes exclusively with GH and prolactin, and it is found in association with the secretory vesicle, as shown by double-immunofluorescence and electron microscopy staining. In sporadic pituitary adenomas, however, AIP is expressed in all tumor types. In addition, whereas AIP is expressed in the secretory vesicle in GH-secreting tumors, similar to normal GH-secreting cells, in lactotroph, corticotroph, and nonfunctioning adenomas, it is localized to the cytoplasm and not in the secretory vesicles. CONCLUSIONS: Our functional evaluation of AIP mutations is consistent with a tumor-suppressor role for AIP and its involvement in familial acromegaly. The abnormal expression and subcellular localization of AIP in sporadic pituitary adenomas indicate deranged regulation of this protein during tumorigenesis.