Villous adenoma of the main pancreatic duct: a clue to the pathogenesis of pancreatic malignancy.

We describe the case of a 78 year old woman with a severely dysplastic villous adenoma of the duct of Wirsung presenting with abdominal pain, emesis, weight loss, and hyperamylasemia. Abdominal ultrasound, computed tomography, and endoscopic retrograde cholangiopancreatography suggested an intraductal lesion in the head of the pancreas with a dilated distal duct. The patient underwent uncomplicated pancreaticoduodenectomy and has done well. A review of the literature on benign and malignant neoplasms of the main pancreatic duct allows formulation of the typical clinical syndrome, appropriate diagnostic work-up, treatment, and prognosis of patients with these rare lesions. The pancreatic ductal epithelium can present the full spectrum of lesions along the pathogenetic route to malignancy. This is evidence for the presence of an adenoma-to-carcinoma sequence in the pancreas analogous to that which exists in the colon.