The usefulness of endoscopic ultrasound-guided fine-needle aspiration for the diagnosis of pancreatic neuroendocrine tumors based on the World Health Organization classification

Objectives: Biological behavior of pancreatic neuroendocrine tumors (Pan NETs) is difficult to predict on morphology alone. The assessment of proliferation by the Ki-67 proliferation index (PI) is considered to be an important prognostic parameter in these tumors and has been endorsed by the 2017 World Health Organization (WHO) grading system for Pan NETs. Although widely accepted on surgical specimens, there is varied opinion on grading of these tumors on cytology samples. This study aimed at classification and grading of Pan NETs on endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) using the recent 2017 WHO criteria and assess the reliability of Ki-67 grading by comparing it with histology samples wherever available. Material and Methods: Search of cytopathology lab records over a 3-year period (June 2015–May 2018) revealed 33 cases of pancreatic NETs diagnosed on EUS-FNA specimens. Using the guidelines of 2017 WHO classification and grading of Pan NETs, retrospective grading of these Pan NETs was done. They were graded as Grades 1, 2, and 3 well differentiated Pan NETs and poorly differentiated Grade 3 neoplasms based on Ki-67 PI and cytomorphology. Cytomorphological features were compared across the three grades. The cytological grading was then compared with the histological grading where available. Results: Ki-67 grading on cytology was done in 32 cases (22 on cell block and 10 on smears), of which 19 (59.4%) were Grade 1, 8 (25%) were Grade 2, and 5 (15.6%) were Grade 3 tumors. The most common cytomorphological features observed in Grade 1 tumors were small round uniform cells with granular chromatin and prominent plasmacytoid morphology. As the grade increased, tumor cells showed increased pleomorphism, angulated nuclei, and less frequent plasmacytoid cells. Histopathology (biopsy/resected specimens) was available in 11 of the 32 cases. Comparison of grading on cytology and histology showed concordance in ten of the 11 cases (k value = 0.862). Conclusion: Our data suggest that grading of Pan NETs by assessing Ki-67 PI on cytology samples collected by EUS-FNA shows good agreement with that measured on histology samples.

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Role of Fine-Needle Aspiration in the Surgical Management of Pancreatic Neuroendocrine Tumors: Utility and Limitations in Light of the New World Health Organization Classification

Archives of Pathology & Laboratory Medicine ◽

10.5858/arpa.2013-0300-oa ◽

2014 ◽

Vol 138 (7) ◽

pp. 896-902 ◽

Cited By ~ 8

Author(s):

Terence N. Moyana ◽

Wayne S. Kendal ◽

Avijit Chatterjee ◽

Derek J. Jonker ◽

Jean A. Maroun ◽

...

Keyword(s):

Minimally Invasive ◽

Fine Needle Aspiration ◽

New World ◽

Preoperative Evaluation ◽

Needle Aspiration ◽

World Health ◽

Pancreatic Neuroendocrine Tumors ◽

World Health Organization Classification ◽

Fine Needle ◽

Health Organization

Context.—Pancreatic neuroendocrine tumors (Panc-NETs) are rare and tend to get overshadowed by their more prevalent and aggressive ductal adenocarcinoma counterparts. The biological behavior of PancNETs is unpredictable, and thus management is controversial. However, the new World Health Organization classification has significantly contributed to the prognostic stratification of these patients. Concurrently, there have been advances in surgical techniques for benign or low-grade pancreatic tumors. These procedures include minimally invasive and parenchyma-sparing operations such as laparoscopy and enucleation. Objective.—To report on the utility and limitations of fine-needle aspiration in the preoperative evaluation and management of PancNETs. Design.—This was a retrospective review of our institutional tumor database from 2002 to 2012. There were 25 cases of PancNETs that were localized and staged by medical imaging and diagnosed by fine-needle aspiration. Results.—Fourteen patients underwent laparotomy, with some requiring only limited surgery; 4 had laparoscopic resections; 4 were serially observed without surgical intervention; and another 3 were inoperable. After a mean follow-up of 37 months, more than half of the patients had no evidence of disease, including most of those who underwent minimally invasive surgery. Conclusions.—Fine-needle aspiration is a useful diagnostic adjunct to medical imaging in the preoperative evaluation and management of PancNETs. However, there are limitations with regard to grading PancNETs using this technique.

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