A case of serous cystic neoplasm with tumor growth acceleration leading to extrapancreatic invasion.

Serous cystic neoplasm (SCN) is a potentially malignant and invasive disease. However, there are no established guidelines regarding the surgical management of SCN. Here, we report a case of SCN with jejunal invasion that ultimately required a distal pancreatectomy with partial resection of the jejunum. The patient was a 65-year-old female who was referred to our department after a diagnosis of SCN in the pancreatic tail. CT and MRI showed a 75-mm multifocal cystic mass with calcifications; the splenic vein and left adrenal vein were entrapped within the tumor. Furthermore, the tumor was in contact with the beginning of the jejunum. Finally, she underwent a posterior radical antegrade modular pancreatosplenectomy with a partial wedge-shaped resection of the jejunum. Histological findings indicated serous cystadenoma. In addition, the tumor cells were found to have infiltrated the jejunal muscularis propria in some areas, suggesting that the tumor had malignant potential. Currently, 14 months have passed since surgery and there is no evidence of metastasis or recurrence. Surveillance and the decision to perform surgical resection should be made based on tumor size and growth rate to avoid malignant transformation as well as to provide SCN patients with organ-sparing, less invasive surgery.