EUS-guided fine needle tattooing (EUS-FNT) for preoperative localization of small pancreatic neuroendocrine tumors (p-NETs): a single-center experience

BACKGROUND and study aims Pancreatic neuroendocrine tumors (pNETs) can be difficult to detect intra-operatively. The aim of this paper is to evaluate the safety and efficacy of preoperative endoscopic ultrasound guided fine needle tattooing (EUS-FNT) to facilitate intra-operative detection of pNETs. PATIENTS AND METHODS Sixteen patients with pNETs (8 insulinoma and 8 non-functional pancreatic neuroendocrine tumors) underwent EUS-FNT. The procedure was carried out using the conventional curvilinear EUS. Tattooing was performed by intralesional injection of 1-2 mL of Spot® ink (Spot®, GI Supply, Comp Hill, PA, US) using a standard 22 gauge EUS-FNA needle. RESULTS All identified pNETs could be tattooed in one session. The procedure was well tolerated in all patients without any complication. The time interval between tattooing and surgery was between 1 and 565 days (mean of 52 days). Nine patients underwent open and seven laparoscopic surgery. The tattooed lesions could be recognized in all but one patient. In one patient, a small hematoma secondary to the EUS-FNT was observed. Pathological examination of the resection specimen showed local R0 resection in all cases, and no interference with the specimen evaluation was encountered. CONCLUSIONS Our results suggest that EUS-guided FNT is a safe and useful method to mark preoperatively small (≤ 2 cm) pNETs.