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Pancreatic neuroendocrine tumours: a comparison of cytological classification systems
  1. Lauren Ackroyd1,
  2. Matthew Hanks1,
  3. Andrei Bancu1,
  4. Marium Khan1,
  5. Saira Sajid1,
  6. Dileep N Lobo2,3,
  7. Abed M Zaitoun1,2
  1. 1Department of Cellular Pathology, Nottingham University Hospitals NHS Trust, Queen’s Medical Centre, Nottingham, UK
  2. 2Nottingham Digestive Diseases Centre, Division of Translational Medical Sciences, School of Medicine, University of Nottingham, Nottingham, UK
  3. 3Division of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
  1. Correspondence to Dr Abed M Zaitoun, Cellular Pathology, Nottingham University Hospitals, Nottingham, UK; Abd.Zaitoun{at}


Aims Cytological classification systems provide a standardised interpretation framework for reporting cytological specimens. Three well-known classification systems can be applied when reporting pancreatic cytology. This study aimed to compare the accuracy of these classification systems (C1–C5 system, the Papanicolaou system and the WHO classification) for the assessment of pancreatic neuroendocrine lesions.

Methods We analysed 73 pancreatic neuroendocrine tumour resections, 49 of which had corroborative cytology available, reported over a 12-year period, at a single UK tertiary referral centre. Each cytology case was classified using the aforementioned systems. The final tumour grade allocated at resection was used to assess and compare the accuracy of each cytological classification system.

Results Cytological assessment accurately reported 77.6% of neuroendocrine lesions as category IVB (neoplastic - other) on Papanicolaou grading, 77.6% as C5 (malignant) lesions and 85.7% as VII (malignant) on WHO grading. 74.3% of resected tumours were grade 1, 17.1% grade 2 and 8.6% grade 3. Complete resection was achieved in 80.8% of cases.

Conclusions The results demonstrated that the WHO classification appeared to provide reduced ambiguity when compared with both ‘C’ and Papanicolaou classification systems; with a lower proportion of cases being classified as suspicious of malignancy as opposed to malignant. The Papanicolaou system was able to supersede the other two systems through its ability to distinguish neuroendocrine tumours from more aggressive entities such as pancreatic adenocarcinoma, thus, offering flexibility in management while still retaining a similar level of accuracy to the WHO classification system in distinguishing benign from malignant lesions.

  • Neuroendocrine
  • Classification
  • Pancreatic Neoplasms

Data availability statement

Data are available on reasonable request. Data will be available for sharing on reasonable request to

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Data availability statement

Data are available on reasonable request. Data will be available for sharing on reasonable request to

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  • Handling editor Vikram Deshpande.

  • X @DL08OMD

  • Contributors Study design: LA, MH, DNL and AMZ. Application for ethical approval: DNL. Data collection: LA and MH. Data interpretation: all authors. Writing of manuscript: LA, MH, DNL and AMZ. Critical Review: all authors. Final approval of submitted manuscript: all authors.

    AMZ is responsible for overall content as the guarantor.

  • Funding This work was supported by the National Institute for Health Research Nottingham Biomedical Research Centre (grant number NIHR203310) and a charitable grant from the Legacy of Norton and Anne Collier.

  • Disclaimer The funders had no role in the design or conduct of the work, or in the decision to publish. This paper presents independent research. The views expressed are those of the authors and not necessarily those of the funders, NHS or the Department of Health.

  • Competing interests DNL has received an unrestricted educational grant from B. Braun for unrelated work. He has also received speaker’s honoraria for unrelated work from Abbott, Nestlé and Corza. No other competing interests declared.

  • Patient and public involvement statement None

  • Provenance and peer review Not commissioned; externally peer reviewed.