Advances in the cytologic diagnosis of gastroenteropancreatic neuroendocrine neoplasms

Abstract

Two‐thirds of neuroendocrine neoplasms arising in the human body originate from the gastrointestinal system or pancreas. Gastroenteropancreatic neuroendocrine neoplasms are heterogeneous, comprising both well differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). The clinical presentation, molecular characteristics, and behavior are distinct for NETs and NECs. Fine‐needle aspiration is an important modality for the primary diagnosis and staging of these neoplasms and can provide information of prognostic and therapeutic significance. Our evolving understanding of neuroendocrine neoplasm biology has led to several iterations of classification. In this review, new concepts and issues most relevant to cytology diagnosis of gastroenteropancreatic neuroendocrine neoplasms are discussed, such as newer detection methods that aid in diagnosis and staging, recent changes in World Health Organization classification, practical issues related to grading these neoplasms on cytology, guidelines for diagnostic reporting, and panels of immunohistochemical stains for the diagnosis of metastasis. The current understanding of genetic and epigenetic events related to tumor development and potential applications for cytology also are presented as they relate to prognostication and recent therapeutic advances.

Cystic hepatic metastases in treatment naïve neuroendocrine tumor: Cytomorphology clubbed with cell block immunocytochemistry clinches the diagnosis

“…Evaluation of Ki-67 index on cytology smears/cell blocks can predict patient survival. 14 Cytologic diagnosis of metastatic NET aided further work-up locating primary in the duodenum and timely initiating appropriate therapy in the present case. Somatostatin receptor-based imaging is employed for the detection and staging of primary NETs.…”

Fibrous Extracellular Spheroids in an Endoscopic Ultrasound-Guided Pancreatic Fine Needle Aspiration Correlating to a Gyriform Pancreatic Endocrine Tumor with a Unique Cobblestone Pavement Growth Pattern

“…Gastroenteropancreatic neuroendocrine neoplasms occur infrequently, but their incidence has increased six-fold over the last three decades [6]. Reported risk factors for PanNENs include tissue injury, germline predisposition, and others.…”

“…Reported risk factors for PanNENs include tissue injury, germline predisposition, and others. In the United States, neuroendocrine neoplasms of the rectum and small intestine have the highest incidence with more cases reported than for neuroendocrine neoplasms of the pancreas and other gastrointestinal sites [6]. Increases in detection rates of asymptomatic pancreatic tumors account in part for the associated increases in incidence of neuroendocrine tumors.…”

Nomogram for preoperative estimation of histologic grade in gastrointestinal neuroendocrine tumors

“…Neuroendocrine tumors (NETs) are heterogeneous tumors arising in the secretory cells of the diffuse neuroendocrine system. About two-thirds of NETs which originate in the gastrointestinal system or pancreas ( 1 , 2 ). Over the past few decades, the incidence of gastroenteropancreatic neuroendocrine tumors is increasing ( 3 , 4 ), among which gastrointestinal neuroendocrine tumors (GI-NETs) have been the second most common GI malignant tumor ( 5 , 6 ).…”