Pseudoneoplastic proliferation of endocrine cells in pancreatic fibrosis

Twenty cases of florid pancreatic endocrine neoformation and hyperplasia in a background of pancreatic fibrosis were culled from a review of 70 cases of pancreatic fibrosis, atrophy, chronic inflammation, and duct obstruction and 29 cases of pancreatic islet cell hyperplasia and neoplasia. Three of these cases had morphologic features suggestive of neoplasia. The phenomenon of endocrine tissue proliferation in a setting of exocrine tissue destruction and fibrosis, especially that secondary to major exocrine duct obstruction is reviewed. The criteria for diagnosis of endocrine neoplasia vs. hyperplasia and the attendant biologic continuum, including applicability of immunohistochemical studies, are discussed.