Pancreatic neuroendocrine tumors(p NETs) are particularly rare. The various forms of PNETs, such as cystic degeneration, make differentiation from other similar pancreatic lesions difficult. We can detect small lesions by endoscopic ultrasound(EUS) and obtain preoperative pathological diagnosis by EUS-guided fine needle aspiration(FNA). We describe, here, an interesting case of p NET in a 42-year-old woman with no family history. Computed tomography and magnetic resonance imaging revealed an 18 mm × 17 mm cystic lesion with a nodule in the pancreatic tail. Two microtumors about 7 mm in diameter in the pancreatic body detected only by EUS, cystic rim and nodules all showed similar enhancement on contrast-harmonic EUS. Preoperative EUS-FNA of the microtumor was performed, diagnosing multiple p NETs. Macroscopic examination of the resected pancreatic body and tail showed that the cystic lesion had morphologically changed to a 13-mm main nodule, and 11 new microtumors(diameter 1-3 mm). Microscopically, all microtumors represented p NETs. From the findings of a broken peripheral rim on the main lesion with fibrosis, rupture of the cystic p NET was suspected. Postoperatively, pituitary adenoma and parathyroid adenoma were detected. The final diagnosis was multiple grade 1 p NETs with multiple endocrine neoplasia type 1. To the best of our knowledge, no case of spontaneous rupture of a cystic p NET has previously been reported in the English literature. Therefore, this case of very rare p NET with various morphological changes is reported.