Serous cystadenoma of the pancreatic head associated with pancreatic duct atresia and acinar cell loss: a case report

BACKGROUND: Serous cystadenoma (SCA) of the pancreas is typically a benign neoplasm, and variants are exceptionally rare. While tumors in the pancreatic head often cause upstream ductal dilatation and parenchymal atrophy due to obstruction, the concurrent presentation of SCA with congenital distal pancreatic duct atresia and complete acinar cell loss is unique. We report this case to highlight a potential congenital pathogenesis linking ductal developmental defects to the formation of these lesions. CASE PRESENTATION: A 56-year-old woman presented with persistent right upper abdominal distension and discomfort lasting over one year. She had a 20-year history of an abdominal mass and had undergone two previous unsuccessful surgical interventions, including a palliative bypass and an aborted resection. Preoperative imaging revealed a large cystic-solid mass in the pancreatic head. Intraoperative exploration identified a 12-cm lesion replacing the pancreatic head and neck, accompanied by complete fatty replacement of the pancreatic body and tail. The patient underwent en bloc pancreaticoduodenectomy with partial portal vein resection and synthetic vascular graft reconstruction. Histopathological examination confirmed the diagnosis of SCA. Notably, the distal pancreatic tissue exhibited a complete absence of acini and visible ductal structures, while islet cells were preserved. Postoperative recovery was uneventful, and at the 12-month follow-up, the patient remained disease-free with preserved endocrine function despite the loss of exocrine function. CONCLUSIONS: This case illustrates the rare coexistence of a SCA with congenital distal pancreatic duct atresia and acinar cell depletion. The preservation of islet function amidst complete exocrine loss supports a developmental anomaly rather than obstruction-induced atrophy. This association suggests that congenital ductal defects may predispose patients to SCA formation. Surgical resection remains the optimal strategy for the diagnosis and management of atypical cystic pancreatic lesions with uncertain biological behavior.