%0 Case Reports
%T Recurrent gastric amphicrine tumor with neuroendocrine and pancreatic acinar cell differentiation and somatic MEN1 inactivation arisen during immunotherapy.
%A Mastrosimini MG
%A Mafficini A
%A Tondulli L
%A Milella M
%A Piccoli P
%A Mattiolo P
%A Fassan M
%A Hong SM
%A Scarpa A
%A Luchini C
%J Virchows Arch
%V 483
%N 3
%D 2023 Sep 15
%M 37581694
%F 4.535
%R 10.1007/s00428-023-03624-4
%X Amphicrine neoplasms (ANs) are poorly understood epithelial malignancies composed of cells with co-existing exocrine-neuroendocrine features. Here, we report a recurrent mucin-producing gastric amphicrine tumor co-expressing neuroendocrine (chromogranin-A, synaptophysin, and CD56) and pancreatic acinar cell (BCL10 and trypsin) markers, arisen in a 64-year-old woman during adjuvant immunotherapy for melanoma. Ki-67 was < 2%. The gastric background context was atrophic gastritis. Next-generation sequencing showed MEN1 mutation (p.P71fs*42) coupled with loss of heterozygosity. The key lessons were as follows: (1) gastric ANs can show the co-existence of exocrine mucin-producing elements with neuroendocrine and pancreatic acinar differentiation; (2) they may represent a new entity arising in the context of atrophic gastritis and during immunotherapy; (3) they should be considered in the diagnostic workup of gastric neuroendocrine tumors; and (4) their molecular profile can show striking similarities with well-differentiated neuroendocrine tumors. These findings may be of help to improve the knowledge and the biological taxonomy of ANs.