Mucinous cystic neoplasm of the pancreas activated during pregnancy

The characteristic histological feature of pancreatic mucinous cystic neoplasm (MCN) is ovarian-like stroma (OS) underlying the epithelium and existence of estrogen receptors and progesterone receptors in the nucleus of OS. We experienced a case of pancreatic MCN which was activated during pregnancy and confirmed the existence of estrogen receptors and progesterone receptors. In cases with potential factors for malignancy, surgical resection of MCN may be needed during pregnancy. On the other hand, in cases without these, as female sex hormones may have an influence on the behavior of pancreatic MCN during pregnancy, the timing of surgery should be decided on a case-by-case basis, taking into consideration the status of the malignancy, the stage of the pregnancy, and the condition of the mother and fetus.