Laparoscopic Spleen-Preserving Distal Pancreatectomy for Mucinous Cystic Neoplasm With Unexpected Immunoglobulin G4-Related Periarteritis of the Splenic Artery: A Case Report.

Unexpected vascular lesions may complicate standard laparoscopic pancreatic procedures. We report a case of mucinous cystic neoplasm (MCN) treated with laparoscopic spleen-preserving distal pancreatectomy (LSPDP) in which unrecognized immunoglobulin G4 (IgG4)-related periarteritis of the splenic artery caused difficulty during vascular division. A 76-year-old woman underwent LSPDP for MCN. Preoperative computed tomography demonstrated circumferential soft-tissue thickening along the splenic artery. Intraoperatively, the splenic artery was deeply embedded within the pancreatic parenchyma, making the Kimura technique impractical; therefore, the Warshaw technique was selected. However, the splenic artery demonstrated marked circumferential wall thickening, precluding safe division with ligation or clipping alone. The artery was ultimately divided using a vascular stapler. Histopathological examination revealed low-grade MCN and IgG4-related periarteritis involving the splenic artery. This case highlights that IgG4-related periarteritis should be considered when unexplained perivascular soft-tissue thickening is identified preoperatively, as it may significantly alter intraoperative strategy during LSPDP.