Pancreatic cystic neuroendocrine tumors: Preoperative diagnosis with endoscopic ultrasound and fine-needle immunocytology

Background Pancreatic cystic neuroendocrine tumors (CNETs) are rare premalignant conditions. Computed tomography (CT) occasionally demonstrates the hypervascular border characteristic of NETs. Endoscopic ultrasound (EUS) with fine-needle aspiration and immunocytology may be a more consistent means to establish the diagnosis, but no data on the role of EUS are available. This report represents the largest series of CNETs treated to date, documents the role of EUS in preoperative diagnosis, and describes current management. Methods Retrospective review of our experience with CNETs treated at an academic center between 1999 and 2006. Results Thirteen patients with CNETs were identified. One had symptoms consistent with a functional tumor; the others were nonfunctional. Twelve were detected by CT; only three had peripheral hypervascularity. Nine were studied with preoperative EUS/immunocytology; each of these demonstrated strong staining for chromogranin and synaptophysin. All were resected: four by pancreaticoduodenectomy, one by total pancreatectomy, and one by enucleation. Perioperative morbidity occurred in 39%. Perioperative mortality was 0%. Average follow-up was 3.3+0.5 years. One patient had late hepatic recurrence and ultimately died of disease. Two developed recurrent NET in the context of MEN I and required additional surgery. Twelve are alive with no evidence of disease. Conclusions EUS-guided immunocytology with staining for neuroendocrine markers is an accurate method to establish the diagnosis of CNET preoperatively. Short- and long-term outcomes after resection are excellent.