Lipid-rich variant of pancreatic endocrine tumour with inhibin positivity and microscopic foci of microcystic adenoma-like areas: emphasis on histopathology

Abstract

Pancreatic endocrine tumours (PETs) are uncommon tumours with typical morphology characterised by relatively uniform cuboidal cells arranged in nests and festoons, with distinctive nuclear salt-and-pepper chromatin. A lipid-rich variant poses diagnostic difficulties in the midst of other pancreatic tumours and metastatic goblet cell carcinoid. A 22-year-old man presented with symptoms of abdominal pain and jaundice. His liver function test and blood glucose level were normal, but computed tomography of the abdomen suggested the presence of a tumour in the head of the pancreas. Specimen obtained by pancreaticoduodenectomy revealed an infiltrating yellow-tan tumour composed of nests and a cribriform arrangement of polygonal vacuolated cells with pyknotic nuclei, along with focal classical areas of PET. Two foci of early serous microcystic adenoma were seen. Immunohistochemistry contributed to the arrival of a conclusive diagnosis. Von Hippel-Lindau disease was excluded in our patient, as other supportive classical features of the syndrome were absent.