Neuroendocrine tumors involving the gastroenteropancreatic tract: a clinicopathological evaluation of 773 cases

OBJECTIVE Description of some of the clinical pathological characteristics of neuroendocrine tumors of the gastroenteropancreatic tract in Brazilian patients. INTRODUCTION Neuroendocrine tumors arise in many organs and share common pathological features. In 2010, the World Health Organization published a new classification for neuroendocrine tumors using a three-tiered system that applies the terms neuroendocrine tumor Grade 1, neuroendocrine tumor Grade 2, and neuroendocrine carcinoma. The tumor grades are based on their mitotic rate and the Ki-67 index. In Brazil, information on neuroendocrine tumors of gastroenteropancreatic tract is scarce. METHODS This study investigated clinicopathological features of 773 Brazilian gastroenteropancreatic neuroendocrine tumor cases from all the geographic regions of Brazil. All of the cases emerged from the files of a single institution (a large pathology reference laboratory) between 1997 and 2009. In addition, the gastroenteropancreatic neuroendocrine tumors were graded according to the new 2010 World Health Organization classification. RESULTS Overall there were a higher number of neuroendocrine tumors in female over male. The lower ages were seen in patients with appendiceal tumors. The most common anatomic location involved was stomach followed by small and large intestines. All cases involving the appendix were of grade 1 and 92.1% of the neuroendocrine tumors of the esophagus were neuroendocrine carcinomas (grade 3). CONCLUSIONS In this series, the proportion of NET cases in the total number of surgical pathology cases at our institution over the past 12 years is increasing.