[An unusual "tumor-like finding" between the head of the pancreas and the duodenal wall].

A 48-year-old woman complained of right-sided upper abdominal pain and recurrent vomiting, and had lost 10 kg in 4 months. Ultrasound and computed tomography showed a solid, space-occupying lesion in the head of the pancreas, not separable from the duodenum. Despite thorough investigation the nature of the lesion remained obscure. Operation revealed a divided pancreas with stenosis of the accessory duct at the papilla. Histological examination showed pseudosarcomatous myofibroblastic proliferation within the duodenal wall in the vicinity of a duodenal wall cyst which had been destroyed by inflammation. In cases of divided pancreas it is the accessory duct which drains the main bulk of the pancreas, while the main duct carries little or no secretion; the stenosis of the accessory duct in this patient had therefore led to low-grade pancreatitis involving the head of the pancreas.