Dear Editor,

We are grateful for the helpful comments of Varas et al. ¹ with regard to the phenotype of cystic pancreatic neuroendocrine tumors (CPNT) reported in a recent meta-analysis of 436 patients ².

Varas et al. highlight the lower incidence of CPNT diagnosed incidentally in 135 patients (44.6%) in comparison with a recent series of 49 patients with an incidental tumor diagnosis of 56.5% ³.

The reason why the percentage of incidental tumors was lower in our analysis is due to the fact that the study was based on all resected cases between 1945 and September 2016. Since 2000, there has been an increased use of more sensitive diagnostic techniques such as computerized axial tomography, nuclear magnetic resonance imaging and ultrasound endoscopy. This has resulted in a considerable increase in the number of tumors incidentally diagnosed (incidentalomas), with figures reaching 80% in some studies and representing 50% of pancreatic surgeon consultations. These issues are discussed within the discussion section of the meta-analysis ². Before 2000, most CPNT were diagnosed on the basis of digestive symptoms and, logically, were larger in size ⁴.

Furthermore, the phenotype and biological behavior described in our meta-analysis are very similar to those of the 49 cases reported by Paiella ³. These comments reflect the significant increase (4.6 fold) in the prevalence and accumulated incidence of gastrointestinal neuroendocrine tumors, from 1.09/100,000 in 1973 to 6.98/100,000 inhabitants in 2012 ⁵. Nowadays, they have overtaken the incidence of esophageal, gastric and pancreatic cancers. Due to their indolent presentation and frequent incidental diagnosis, these tumors represent a particular challenge for gastroenterologists.