Zhao et al. [111] conducted a study on 55 patients with confirmed MEN1-related insulinomas (78% of them were also diagnosed with primary hyperparathyroidism); the authors showed that 69% were multifocal masses; post-surgery tumor recurrence was identified in 45% of cases; 55% of these subjects had multiple procedures of enucleation; 10% of the individuals with distal resection were associated with post-operatory pancreatic insufficiency (for a mean follow-up of 7 years) [111]. This evidence concerns the gene MEN1 and pancreatic insulinoma.