# Whole-mount pathology

Source: https://onco.cc/terms/whole-mount-pathology/  
OnCo record `whole-mount-pathology` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Slicing the whole removed prostate into complete cross-sections on oversized slides, so each slide shows the entire gland in one piece rather than in fragments. It is the reference standard used to check how well a scan found what was really there.

## Summary

Whole-mount pathology, also called large format histology or whole-mount sectioning, is the examination of tissue sections cut from specimens processed in large tissue cassettes, so that a complete cross-section of the organ sits on a single slide. In prostate cancer it is applied to the radical prostatectomy specimen. A collaborative review of the literature found that whole-mount sections are not superior to standard sections at detecting adverse pathological features, and that their advantage is spatial: they display the architecture of the gland and identify and locate tumour nodules, and the index tumour in particular, more clearly, which makes the pathology far easier to compare with the digital rectal examination, the transrectal ultrasound, the multiparametric magnetic resonance imaging, the operation and the biopsies.

That is why it is the reference standard for imaging accuracy. Johnson and Raman co-registered multiparametric magnetic resonance imaging with whole-mount pathology in 588 consecutive men who had a 3 Tesla scan before radical prostatectomy, giving 1,213 pathologically confirmed tumour foci, and measured per-lesion rather than per-patient sensitivity. The scan detected 45 percent of all foci (95 percent confidence interval 42 to 47) and 65 percent of clinically significant lesions (61 to 69), and missed at least one clinically significant focus in 34 percent of men overall and 45 percent of men with multifocal disease. Set against PROMIS's 93 percent per-patient sensitivity for clinically significant cancer, the gap of roughly 30 percentage points is the difference between asking whether a man has a serious cancer and asking where all of it is, and it is precisely the territory in which focal therapy and imaging-only surveillance operate.

The method has limits of its own. Co-registration of a scan with a whole-mount section is imperfect, which biases measured detection downwards by an unknown amount; the specimen shrinks and deforms in processing; a prostatectomy cohort is enriched for intermediate and high-risk disease and cannot report specificity; and standardised annotation protocols show excellent agreement between pathologists for cancer localisation and grading but persistent variability for cribriform growth and intraductal carcinoma.

## Fields

- Kind: Term
- Last checked: 2026-09-25
- Also known as: whole mount; whole-mount sectioning; whole mount histopathology; large format histology; macrosectioning; whole-mount prostatectomy specimen
- Tags: gu; prostate-glossary

## Notes

- Whole-mount is not routine everywhere and does not need to be. It costs more in cassettes, embedding and reporting time and, on the evidence, does not find more adverse features than standard sampling. Where it earns its place is any work that needs the tumour's position rather than only its presence: imaging validation, focal therapy planning, surgical technique audit and the ground-truth datasets that artificial intelligence imaging models are trained on.
- It is also the ground truth behind the machine learning. Prostate imaging models are trained and validated against annotated prostatectomy pathology, so the reliability of the annotation protocol is the ceiling on the model. Standardised protocols reach excellent agreement for localising cancer and substantial agreement on Gleason pattern, and remain a source of disagreement for cribriform and intraductal disease.

## Sources

- Cimadamore et al., European Urology Oncology 2021: added clinical value of whole-mount histopathology of radical prostatectomy specimens, a collaborative review: https://doi.org/10.1016/j.euo.2020.08.003
- Johnson et al., European Urology 2019: detection of individual prostate cancer foci via multiparametric magnetic resonance imaging: https://doi.org/10.1016/j.eururo.2018.11.031
- Ahmed et al., The Lancet 2017 (PROMIS): diagnostic accuracy of multiparametric MRI and TRUS biopsy in prostate cancer: https://doi.org/10.1016/s0140-6736(16)32401-1
- Royal College of Pathologists G084: dataset for histopathology reports for prostatic carcinoma, version 4, October 2024: https://www.rcpath.org/static/8cc88604-2c8d-4df4-a99542df41c102af/G084-dataset-for-histopathology-reports-for-prostatic-carcinoma.pdf

## Connected records

- key papers: [Detection of individual prostate cancer foci via multiparametric magnetic resonance imaging](https://onco.cc/key-papers/paper-johnson-mpmri-individual-foci-eur-urol-2019/), [PROMIS: diagnostic accuracy of multiparametric MRI and TRUS biopsy in prostate cancer](https://onco.cc/key-papers/paper-ahmed-promis-multiparametric-mri-lancet-2017/)
- ideas: [Publish a per-lesion miss rate for every prostate MRI service before it is allowed to guide focal treatment](https://onco.cc/ideas/idea-prostate-per-lesion-mri-audit-before-focal-treatment/)
- terms: [Cribriform growth pattern in prostate cancer](https://onco.cc/terms/cribriform-prostate-cancer/), [Gleason score / Grade Group](https://onco.cc/terms/gleason-grade-group/), [Intraductal carcinoma of the prostate (IDC-P)](https://onco.cc/terms/intraductal-carcinoma-prostate/), [PI-RADS (Prostate Imaging Reporting and Data System)](https://onco.cc/terms/pi-rads/), [Radical prostatectomy](https://onco.cc/terms/prostatectomy/), [Resection margins (R0 / R1 / R2)](https://onco.cc/terms/resection-margins/), [Template mapping biopsy (transperineal template prostate mapping)](https://onco.cc/terms/template-mapping-biopsy/)
- cancers: [Localised prostate cancer, high and very high risk](https://onco.cc/cancers/prostate-high-risk/), [Localised prostate cancer, intermediate risk](https://onco.cc/cancers/prostate-intermediate-risk/), [Localised prostate cancer, very low and low risk](https://onco.cc/cancers/prostate-low-risk/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- fronts: [Diagnostics & Biomarkers](https://onco.cc/fronts/diagnostics/), [Imaging](https://onco.cc/fronts/imaging/), [Surgery & Interventional](https://onco.cc/fronts/surgery/)
- technologies: [MRI](https://onco.cc/technologies/mri/)
- bottlenecks: [AI that is built but not validated or deployed](https://onco.cc/bottlenecks/b-ai-validation/), [Biomarkers are not validated or standardised](https://onco.cc/bottlenecks/b-biomarker-validation/), [Surgery and radiotherapy cure most, get least](https://onco.cc/bottlenecks/b-surgery-radiation-innovation/)

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