Endocrine Abstracts

Pancreatic neuroendocrine tumours (PNETs), although reported with increasing frequency through increased use of abdominal imaging, are rare and uncommon tumours (1 per 100,000 population) representing 1–2% of all pancreatic neoplasms. Preoperative diagnosis is important since a solitary small tumour without evidence of metastatic spread may be suitable for pancreatic preserving surgery such as enucleation or middle segment resection rather than more extensive resection. However, preoperative localisation can be difficult, as these tumours are frequently smaller than 2 cm in diameter and conventional imaging methods such as trans-abdominal ultrasound, computed tomography and magnetic resonance imaging may fail to accurately localise the tumour in up to 40–70% of patients. Endoscopic ultrasound (EUS) has been reported to be highly accurate for the preoperative localization of PNETs, mainly primary insulinomas which frequently are negative on somatostatin receptor scintigraphy. PNETs are identifiable by EUS in 79–95% of suspected cases, and usually appear hypoechoic, round and homogenous, although they may be isoechoic or hyperechoic with irregular margins. EUS guided fine needle aspiration (EUS-FNA) or biopsy (EUS-FNB) can confirm the diagnosis pathologically and provide information to guide the type of surgical intervention. Radiofrequency ablation (RFA) causes thermal coagulative necrosis through the administration of a high-frequency current. Recently new monopolar RFA probes have been developed that can be placed down the working channel of a linear echoendoscope, enabling RFA to be administered under EUS guidance. To date this technique has been shown in several case series to be effective and safe in the management of patients with functional PNETs who have failed multiple medical therapies and cannot undergo surgery due to co-morbidities. Long-term outcome data and further experience are required but EUS-guided RFA and other novel ablative approaches may now be considered for selected cases.