Mucinous cystic neoplasms of the pancreas are rare tumors that tend to occur in young women. They are thought to be responsive to sex hormones. We report a case of a 32-year-old pregnant woman with a 7-month history of pain and a left upper quadrant abdominal mass. She arrived at the emergency department with exacerbation of her symptoms during week 15 of gestation. Findings from ultrasonography and magnetic resonance imaging suggested a pancreatic cyst. Percutaneous aspiration of the cyst fluid yielded mucinous fluid with an elevated carcinoembryonic antigen level. The patient underwent a spleen-preserving distal open pancreatectomy. We present herein a brief review of the current literature on mucinous cystic neoplasms during pregnancy. On the basis of our experience and the existing knowledge of this condition, we advocate resection during the second trimester with splenic preservation.