Pancreatic mucinous cystic neoplasms are cystic lesions which appear commonly in the pancreatic body and tail in middle-aged females, and have a characteristic macroscopic description referred to as "orange like shape", or "cyst in cyst". In 2007, a multi-institutional retrospective observational study of MCN with ovarian type stroma was conducted by the Japan Pancreatic Society. Clinicopathological features and long-term prognosis were described based on 156 collected MCN cases in this study. For the diagnosis of MCN, capturing the characteristic clinical and pathological features using imaging modalities such as US, CT, MRI, and EUS is necessary. Cyst fluid analyses were also considered for difficult cases. Although diagnosing typical MCN is relatively easy, care should be taken when diagnosing atypical cases.
