Spontaneously Ruptured Pancreatic Mucinous Cystic Neoplasm: A Case Report

INTRODUCTION: Pancreatic mucinous cystic neoplasm (MCN) is a cystic tumor of the pancreas typically located in the pancreatic body or tail in middle-aged women. However, MCN rupture is rare. This report describes a case of MCN with spontaneous rupture during follow-up. CASE PRESENTATION: The patient was a 34-year-old woman. Contrast-enhanced computed tomography (CECT) and magnetic resonance imaging (MRI) revealed a 130 mm multifocal cyst in the pancreatic tail. The cyst, characterized by multiple septa and cyst-in-cyst structures, was diagnosed as an MCN. Initially, the patient opted for periodic follow-ups instead of surgical resection. After a gradual increase in cyst size, surgery was scheduled approximately 1 year later. Two days before the scheduled surgery, the patient experienced unexplained lower abdominal pain. Moreover, CECT revealed a shrinking cystic mass in the pancreatic tail along with the presence of ascites, leading to a diagnosis of spontaneous rupture of the pancreatic cyst. No peritonitis was detected, and a distal pancreatectomy was performed 2 days after admission. Pathological examination confirmed that the pancreatic cyst was a noninvasive mucinous cystadenocarcinoma. The abdominal cavity contained large amounts of turbid ascites with neutrophils but no bacterial growth. Strong inflammatory changes were noted at the cyst wall disruption site. Despite the development of a pancreatic fistula (ISGPF Grade BL, Clavien-Dindo Grade II), the patient was discharged from the hospital on postoperative day 16 and remained alive and recurrence-free for 18 months after surgery. CONCLUSION: Spontaneous rupture of an MCN is rare. In this study, we report our case and review previously published cases of MCN rupture. We also discuss the potential causes of the spontaneous rupture in our case.