Endocrine Abstracts

Introduction: MEN1 associated pNETs share a unique profile in comparison to sporadic pNETs. The literature on pNETs in MEN1 is evolving with on-going ambiguities in presentation and management. We present a case series of MEN1 associated pNETs from a tertiary centre of excellence for NETs in the UK.

Methods: Institutional NET database was used for retrospective data analysis for all patients with pNETs associated with MEN1.

Results: Of a total of 1773 patients with NETs, 292 had pNETs with 16 of 292 having genetically proven MEN1. The average age of diagnosis of pNET in MEN1 was mean(S.D.): 34.7(11.5) years with an equal distribution among both sexes (8 men & 8 women). 8 pNETs were diagnosed on radiological surveillance for MEN1 related tumours. 6 pNETs were non-functioning (nfPNETs), 7 gastrinomas & 4 insulinomas (1 both gastrinoma and insulinoma) (2 insulinomas followed by nfPNET recurrence). Biochemical analysis of nfPNET revealed elevated gut hormones (GH) in 3/6. Pancreatic polypeptide (PP) and Chromogranin-B (CGB) were elevated in 2/6 patients and Glucagon in 1/6. 6/16 had multiple pNETs with the tail being the most common site of pNETs (12 tail, 7 head, 7 body). 7 had recurrence after a previous resection after a mean(S.D.) of 14.2(11.5) years. Recurrent tumours were gastrinomas(4/7) and nfPNETs (3/7) (2 after previous insulinoma resection and 1 previous nfPNET). 6/16 pNETs were metastatic (4 gastrinoma and 2 nfPNETs). At least one GH was elevated in all metastatic pNETs (4 gastrin, 1 pancreatic polypeptide & 1 chromogrannin B). No patients with MEN1 related pNET had elevated CGA. Histology of 11/16 pNETs revealed well differentiated NETs (7 Grade 1, 1 Grade 2, 3 no Ki67). Grade 2 pNET was associated with metastatic gastrinoma. There were 2 deaths related to a metastatic thymoma and a gastrinoma respectively.

Conclusion: MEN1 related PNETs from our single centre cohort, had a young age of onset and were more likely to be functioning PNETs, more commonly occurring in the tail of the pancreas. 50% of NfPNETs and all metastatic PNETs had elevated levels of at-least one GH. No patients with MEN1 associated PNET had CGA elevation.