Extrapancreatic gastrinoma with pancreatic islet cell hyperplasia

A case of Zollinger-Ellison syndrome was associated with diffuse islet cell hyperplasia of the pancreas and extrapancreatic gastrinoma. At autopsy, the patient, who had well-documented Zollinger-Ellison syndrome, was found to have gastrinoma in parapancreatic lymph nodes with islet cell hyperplasia but no evidence of pancreatic neoplasm. Possible explanations include the production of a trophic factor by the extrapancreatic gastrinoma, leading to islet cell hyperplasia, or metastasis from a microscopic nodule of gastrin cells that, despite having a "hyperplastic" appearance, exhibited malignant potential.