A brief review of the WHO reporting system for pancreaticobiliary cytopathology

Doing more with less: integrating small biopsies in cytology practice

Cytopathologists are at the forefront of specimen acquisition during many different procedures while providing rapid on site evaluation (ROSE). This has added pressure to cytopathologists as more and more ancillary testing is being requested on smaller amounts of tissue. By focusing on the most common organ sites: lung, head and neck, and pancreas, there is a discussion of what the cytopathologist needs to know to triage tissue successfully. Finally, there is a discussion of the logistical aspects of integrating small biopsies into everyday practice.

Grading pancreatic adenocarcinomas on fine needle aspiration cytology. The outstanding issues

OBJECTIVE

The three-tier grading scheme described in "The Papanicolaou Society of Cytopathology (PSC) System for reporting Pancreaticobiliary Cytopathology" (TPSCRPBC) which remained unchanged following the WHO Reporting System for Pancreaticobiliary Cytopathology (WRPBC) was evaluated on pancreatic adenocarcinomas (PACs) reported on endoscopic ultrasound-guided fine needle aspiration cytology (EUS-FNAC).

METHODS

The Papanicolaou and May Grunwald Giemsa-stained smears from 116 cases of PACs were graded using the three-tier grading scheme laid down by TPSCRPBC/WRPBC. Cases exhibiting multiple grades were assigned primary, secondary and tertiary grades. Each case was assigned a grade score, either by adding the primary and secondary grades, by adding the primary and tertiary grades when the tertiary grade was 3 or by doubling the grade when only one grade existed. Necrosis was estimated semi-quantitatively. The inter-observer reproducibility in grading was evaluated using Kappa and Kendall's tau-c. Correlations between the various grades, the stage of the tumour and the amount of necrosis were assessed using Spearman rho and Kendall's tau-b.

RESULTS

31.89% of cases showed one grade, and 68.11% showed at least two grades. 16.38% showed three grades. The two commonest grade scores were 3 and 5. The inter-observer reproducibility for grading and grade scoring was satisfactory. A positive correlation was noted between the grades and the amount of necrosis. No significant correlation was found between the grades, grade scores and the stage of the tumours.

CONCLUSIONS

The TPSCRPBC/WRPBC grading scheme can be suitably applied to PACs with good inter-observer reproducibility. Cases often show multiple grades in the same tumour.

Echoendoscopic ultrasound pancreatic adenocarcinoma diagnosis and theranostic approach: should KRAS mutation research be recommended in everyday practice?

Background

The impact of KRAS mutation testing on pancreatic ductal adenocarcinoma (PDAC) samples by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for reducing the need to repeat EUS-FNA has been demonstrated. Such testing however is not part of standard practice for endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB).

Objectives

We aim to analyse the proportion of non-contributive samples by EUS-FNB and to evaluate the impact of KRAS mutation testing on the diagnosis, theranostics and survival.

Design

In this retrospective study, the impact on diagnosis and survival of KRAS testing for contributive and non-contributive samples by EUS-FNB was analysed.

Methods

The EUS-FNB samples, combined with KRAS testing using the Idylla® technique on liquid-based cytology from patients with PDAC between February 2019 and May 2023, were retrospectively reviewed. The cytology results were classified according to the guidelines of the World Health Organization System for Reporting Pancreaticobiliary Cytopathology (WHOSRPC).

Results

A total of 85 EUS-FNB specimens were reviewed. In all, 25 EUS-FNB samples did not lead to a formal diagnosis of PDAC according to the WHOSRPC (30.2%). Out of these 25, 11 (44%) could have been considered positive for a PDAC diagnosis thanks to the KRAS mutation test without carrying out further diagnosis procedures. The sensitivity of KRAS mutation testing using the Idylla technique was 98.6%. According to the available data, survival rates were not statistically different depending on the type of mutation.

Conclusion

KRAS mutation testing on liquid-based cytology using the Idylla or equivalent technique, combined with the PDAC EUS-FNB sample, should become a standard for diagnosis to avoid delaying treatment by doing another biopsy. Furthermore, knowledge of the KRAS status from treatment initiation could be used to isolate mutations requiring targeted treatments or inclusion in clinical research trials, especially for wild-type KRAS PDAC.

The rationale for the development and publication of the World Health Organization reporting systems for cytopathology and a brief overview of the first editions of the lung and pancreaticobiliary systems

The International Academy of Cytology has joined with the International Agency for Research on Cancer and the World Health Organization (WHO) to develop international systems for reporting the cytopathology of lung, pancreas and biliary tract, lymph nodes, soft tissue, liver, breast, and kidney and adrenal gland. The WHO recently published the reporting systems for lung and pancreaticobiliary cytopathology. The objectives of this collaboration are to standardize the reporting of cytopathology; improve the quality of reporting by establishing the key diagnostic cytopathological features of entities and neoplasms; provide detailed best-practice guidelines in sampling techniques, specimen handling and processing, and the use of ancillary techniques; and facilitate communication between cytopathologists and clinicians to improve patient care. Each WHO system has defined specific categories and terminology for reporting cytopathology, and each category has an estimated risk of malignancy as far as the current literature allows and a suggested diagnostic management algorithm to assist clinicians. The WHO systems recognize that local medical and pathology infrastructure will vary, particularly in low-income and middle-income countries, and the WHO systems and their diagnostic management recommendations have been developed to allow them to be applied worldwide in all resource settings. The process of the selection of editors and authors and the writing and editing responsibilities has used the same model as that used for the fifth edition WHO Classification of Tumours, to which the WHO cytopathology systems are directly linked. This review provides the rationale and history of this joint International Academy of Cytology, International Agency for Research on Cancer, and WHO cytopathology project and a brief overview of the WHO reporting systems for lung and pancreaticobiliary cytopathology.

Cytomorphologic, immunophenotypical and molecular features of pancreatic acinar cell carcinoma

OBJECTIVES

As a rare tumor in pancreas, pancreatic acinar cell carcinoma (PACC) possesses a distinct molecular feature from pancreatic ductal carcinoma (PDAC). Though the diagnosis of PACC is often established based on cytology specimens, its cytologic diagnosis can be challenging. Furthermore, the correlation between PACC cytomorphology and its unique different molecular alterations have not been fully explored.

METHODS

Cytology features were analyzed in 8 histologically proven PACC and cytohistological correlation was performed. Immunocytochemistry for trypsin, chymotrypsin, BCL10, synaptophysin, chromogranin A, INSM1, β-catenin, and Ki-67 was assessed. Comprehensive molecular profiling and additional targetable treatment biomarker assessment were also performed.

RESULTS

The cohort included 4 mixed acinar-neuroendocrine carcinomas, 3 pure PACCs, and 1 mixed acinar-ductal carcinoma. Immunophenotypical features are consistent with diagnoses of PACC or PACC with neuroendocrine features. Identified genetic alterations included somatic mutations of CTNNB1, TP53, MAP2K1, PTEN, RAC1, germline mutations of NBN and BRAC2, and gene fusion of CCDC6-RET.

CONCLUSIONS

The current study is the first attempt to explore the correlation between the cytomorphology characteristics and molecular features of PACC and a few intriguing findings were observed. Further validation in larger cohorts is warranted.