Pancreatic Neuroendocrine Tumours: The Role of Endoscopic Ultrasound Biopsy in Diagnosis and Grading Based on the WHO 2017 Classification

Abstract

Background: One of the controversial issues in the diagnosis of pancreatic neuroendocrine tumours (pNETs) is the accurate prediction of their clinical behaviour. Objectives: The aim of the study was to evaluate the role of endoscopic ultrasound (EUS) biopsy in the diagnosis and grading of pNETs in a certified ENETS Center. Methods: A prospectively maintained database of EUS biopsy procedures was retrospectively reviewed to identify all consecutive patients referred to a certified ENETS Center with a suspicion of pNET between June 2014 and April 2017. The cytological and/or histological specimens were stained and the Ki-67 labeling index was evaluated. In patients undergoing surgery, the grade obtained with EUS-guided biopsy was compared with the final histological grade. The grade was evaluated according to the 2017 WHO classifications and grading. Results: The study population included 59 patients. EUS biopsy material reached an adequacy of 98.3% and was adequate for Ki-67 evaluation in 84.7% of cases. Twenty-nine patients (49.2%) underwent surgery. Of these, 25 patients had Ki-67 evaluated on EUS biopsy: the agreement between EUS biopsy grading and surgical specimen grading was 84%. Conclusion: EUS biopsy is an accurate method for the diagnosis and grading of pNETs based on the WHO 2017 Ki-67 labelling scheme.

Role of Endoscopic Ultrasound in the Diagnosis of Pancreatic Neuroendocrine Neoplasms

“…Hijioka et al reported that the location of the tumor in the pancreatic head and the presence of rich stromal fibrosis negatively affect the sampling adequacy of EUS-FNA [56]. In recent years, fine-needle biopsy (FNB) needles have been used, which are expected to improve diagnostic ability [57][58][59][60][61][62][63].…”

Experience and future perspectives on the use of the Papanicolaou Society of Cytopathology Terminology System for reporting pancreaticobiliary cytology

“…This is difficult to translate to cytological samples, since change in architecture in cell block sections will obviously have a significant impact on how mitotic activity will be assessed. In addition, studies on the use of immunohistochemical markers such as ki‐67 on cell blocks is still controversial, with most studies showing good concordance between low‐grade G1 tumors, but underestimation of higher grade lesions . Additional studies with larger comparisons of cell block and resection specimens may be needed to clarify the role of using grading in cytology and a possible incorporation of proposed guidelines in the future versions of classification systems.…”

Role of Endoscopic Ultrasound in the Diagnosis of Pancreatic Neuroendocrine Neoplasms

“…Hijioka et al reported that the location of the tumor in the pancreatic head and the presence of rich stromal fibrosis negatively affects the sampling adequacy of EUS-FNA [38]. In recent years, fine-needle biopsy (FNB) needles have been used, which are expected to improve the diagnostic ability [39][40][41][42][43][44][45].…”

“…However, it is almost impossible to count in 50 HPFs with FNA samples, and the Ki-67 proliferation index is usually used in clinical practice. The concordance rate of the Ki-67 index between PNENs measured from EUS-FNA samples and surgical specimens was reported to be 54%-100% [37,[43][44][45][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67] (Table 1), whereas a systematic review reported a rate of 83% [68]. Pooling the data of the studies which compared the Ki-67 LI grades obtained both in EUS-FNA samples and surgical specimen, the concordance rate was 77.5% and the kappa correlation index was 0.65 (95% confidence interval = 0.59 -0.71, P < 0.01) ( Table 2) [37,[43][44][45][49][50][51][52][54][55][56][57][58][59][60][61][62][63][64]…”

“…Table 2. Concordance of PNEN grading between EUS-FNAB specimens and surgical specimens in pooling data [37,[43][44][45][49][50][51][52][54][55][56][57][58][59][60][61][62][63][64][65][66]69]. Grade 1 Grade 2 Grade 3 Total Grade 1 338 88 5 431 Grade 2 32 111 12 155 Grade 3 0 0 23 23 Total 370 199 40 609…”