Cystic Pancreatic Lesions in MEN1: A Distinct pNEN Phenotype — ASN Events
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Cystic Pancreatic Lesions in MEN1: A Distinct pNEN Phenotype (#337)

Jessica Bindra 1 2 3 , Lyndal Tacon 1 3 , Roderick Clifton-Bligh 1 2 3
  1. Department of Endocrinology, Royal North Shore Hospital, Sydney, NSW, Australia
  2. Cancer Genetics and Diagnostics Laboratory, Kolling Institute, Sydney, NSW, Australia
  3. Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia

Pancreatic neuroendocrine neoplasms (pNENs) occur in 50-70% of patients with Multiple Endocrine Neoplasia type 1 (MEN1) and are the leading cause of morbidity and mortality.1 Cystic pancreatic lesions are increasingly recognised in MEN1 and often reported as intraductal papillary mucinous neoplasms (IPMNs), despite potentially representing cystic pNENs. Their biological behaviour and clinical significance remain poorly defined, resulting in uncertainty regarding radiological reporting and management.2 We aimed to characterise the imaging features and clinical behaviour of cystic pancreatic lesions in MEN1 compared with solid pNENs.

We conducted a retrospective single-centre cohort study of patients with MEN1 undergoing pancreatic surveillance at a tertiary referral centre. Pancreatic lesions were classified as solid or cystic (including mixed solid-cystic) using CT or MRI. Clinical characteristics, lesion distribution, 68Ga-DOTATATE uptake, growth, metastases and surgery were compared between groups.

Thirty-six patients with MEN1-associated pancreatic lesions were identified, including 13 (36%) with cystic or mixed cystic lesions. Baseline characteristics, growth and follow-up duration were similar between groups (median 72.0 months [15.8-108.0] in solid pNENs vs 56.0 months [21.0-73.0] in cystic pNENs). Cystic lesions were significantly more likely to arise in the pancreatic tail (p=0.04) and most demonstrated preserved 68Ga-DOTATATE avidity (66.7%), comparable to solid pNENs (75.0%). Metastases and surgical intervention were numerically less frequent in the cystic cohort, although these differences did not reach statistical significance. Resected cystic tumours demonstrated lower Ki-67 indices than solid tumours, although this was not statistically significant.

Cystic pancreatic lesions in MEN1 demonstrate imaging and clinical characteristics consistent with pNENs, including preserved 68Ga-DOTATATE avidity and biological behaviour comparable to solid tumours, while potentially representing a less aggressive phenotype. Our findings suggest that cystic pancreatic lesions in MEN1 should be evaluated as cystic pNENs rather than presumed IPMNs, with important implications for surveillance and management. Larger multi-centre studies are warranted to validate these findings.

  1. Goudet P, Murat A, Binquet C, et al. 2010 Risk factors and causes of death in MEN1 disease. A GTE (Groupe d’Etude des Tumeurs Endocrines) cohort study among 758 patients. World J Surg 34 249–255. (https://doi.org/10.1007/s00268-009-0290-1)
  2. van Vliembergen ENM, Pieterman CRC, van de Ven AC, Braat AJAT, Valk GD, de Laat JM. The natural course of cystic pancreatic neuroendocrine tumours in MEN1. Endocr Oncol. 2025 Feb 4;5(1):e240050. (https://doi.org/10.1530/EO-24-0050).