Robot-Assisted Spleen-Preserving Distal Pancreatectomy for an Epithelial Cyst Arising from an Intrapancreatic Accessory Spleen: A Case Report.

INTRODUCTION: Epithelial cysts arising from an intrapancreatic accessory spleen (ECIPAS) are rare and often misdiagnosed as pancreatic cystic neoplasms because their imaging features frequently overlap. When malignancy cannot be ruled out, surgical resection is generally indicated, and minimally invasive approaches have become an appropriate treatment option. We report a case of ECIPAS initially suspected to be a mucinous cystic neoplasm (MCN), successfully treated with spleen-preserving distal pancreatectomy using the hinotori Surgical Robot System.

CASE PRESENTATION: A 63-year-old woman was incidentally found to have an 18-mm cystic lesion in the pancreatic tail during preoperative imaging for laparoscopic cholecystectomy 2 years earlier. The lesion gradually enlarged to 30 mm over 2 years of serial follow-up. MRI demonstrated a "cyst-in-cyst" morphology without communication with the main pancreatic duct. Contrast-enhanced CT revealed a thick-walled cyst with internal septal calcifications but no solid components. Serum carbohydrate antigen 19-9 and carcinoembryonic antigen levels were within normal limits. Based on the imaging features and lesion growth, we suspected MCN and indicated surgical resection. Consequently, robot-assisted spleen-preserving distal pancreatectomy (Robo-SPDP) was performed using the hinotori system, following the Kimura technique. The procedure was completed safely without any intraoperative complications. Histopathological examination revealed a cyst lined by flattened to columnar epithelium, with an underlying splenic sinus structure confirmed by CD8 immunostaining. Ovarian-type stroma was absent, excluding MCN and establishing a diagnosis of ECIPAS. The postoperative course was uneventful, and the patient was discharged on POD 10.

CONCLUSIONS: This case highlights the importance of considering ECIPAS in the differential diagnosis of pancreatic cystic lesions, particularly when imaging findings resemble cystic neoplasms. When malignancy cannot be ruled out, surgical resection is recommended and minimally invasive spleen-preserving distal pancreatectomy is a reasonable therapeutic option. Furthermore, robotic assistance appeared to be a safe and effective surgical approach facilitating precise dissection and reliable preservation of the splenic vessels.