Hypervascular solid-appearing serous cystadenoma as a mimic of nonfunctioning pancreatic neuroendocrine tumour: a systematic review

BACKGROUND: Solid pancreatic serous cystadenoma (SCA) may present as a hypervascular mass and mimic nonfunctioning pancreatic neuroendocrine tumour (NF-pNET), potentially leading to pancreatic resection for benign disease. We synthesized the available evidence on this diagnostic pitfall. METHODS: A PRISMA 2020-aligned systematic review searched MEDLINE, Embase, and Web of Science (1 January 2000-1 December 2025). We included comparative cohorts of pathology-proven SCA versus NF-pNET reporting CT/MRI discriminative features and case reports/series of pathology-proven SCA preoperatively interpreted as NF-pNET. Comparative cohorts and case reports/series were synthesized separately; no meta-analysis was performed. RESULTS: Ga-DOTA-peptide uptake in 17/39 (43.6%), and EUS-guided sampling was diagnostic in 9/17 (52.9%). CONCLUSIONS: NF-pNET-mimicking SCA is an uncommon but clinically consequential benign mimic. In the available retrospective comparative cohorts of resected, pathology-proven lesions, lower unenhanced CT attenuation (and attenuation ratios) and higher DWI-ADC values consistently favored SCA over NF-pNET, whereas arterial hyperenhancement and positive somatostatin receptor imaging uptake were not specific. These findings may support cautious multiparametric assessment in selected hypervascular solid-appearing pancreatic lesions, but should not be applied as definitive diagnostic thresholds without external validation.