925 Incremental Value of Endoscopic Ultrasound in Detecting Pancreatic Lesions in Patients With MEN1

INTRODUCTION: Multiple endocrine neoplasia type 1 is an inherited disorder that affects the endocrine glands caused by a mutation in the MEN1 gene. MEN1 is associated with pituitary, parathyroid and pancreatic lesions (specifically tumors of islet cells and neuroendocrine tumors) and the prevalence of pancreatic lesions can range as high as 75%. Currently, CT and MRI are used to investigate pancreatic lesions in MEN1. Endoscopic ultrasound can also be used to assess the pancreas and also allows for tissue sampling. The main disadvantage of EUS is that it is invasive and requires an endoscopy with anesthesia to perform. In this study, we examine the incremental value of performing EUS in patients with MEN1 who were referred after CT or MRI. METHODS: This was a retrospective study of all patients with a mutation-proven MEN1 diagnosis who underwent EUS between 2009 and 2018. Patients who had previous resection for pancreatic lesions were excluded. The cross-sectional image closest to the date of the EUS was used as a comparison. Relevant data including lesion characteristics were extracted. The location of the lesions were also recorded as multiple locations could affect future treatment options. RESULTS: A total of 42 patients with MEN1 underwent EUS for pancreatic lesions. The mean age was 51.9 years (SD +/- 13.7) and 24 (57%) patients were female. A total of 31 patients had a CT while 11 patients had an MRI to compare to EUS. For patients who underwent CT followed by EUS, CT showed 45 lesions (1.5 lesions per procedure) while EUS showed 78 pancreatic lesions (2.5) (P < 0.05). The mean size of the largest lesion was 22.4 mm (SD 14) with EUS, and 16.7 mm (SD 17). In 14 cases, EUS saw a lesion in an area of the pancreas that was not seen on CT, while only in 3 cases the CT saw a lesion in a location not seen on EUS. Twenty-five (81%) of patients in the CT group underwent FNA to obtain cytology. For patients who underwent MRI followed by EUS, MRI showed 19 lesions while EUS showed 48 lesions (P < 0.05). The mean size of the largest lesion was 14.3 (SD 10.5) with EUS, and 6.9 with MRI (SD 7.8). In 8 cases, EUS saw a lesion in a territory that was not seen in on MRI. Six (55%) patients in the MRI comparison underwent FNA. Overall, no complications were noted from performing EUS or FNA. CONCLUSION: Despite advances in imaging by CT and MRI, EUS continues to play an important incremental role in detecting and mapping pancreatic lesions in patients with MEN1.