title: Intrapancreatic accessory spleen: mimic of pancreatic endocrine tumor diagnosed by endoscopic ultrasound-guided fine-needle aspiration biopsy.
abstract: Intrapancreatic accessory spleen forms a well-defined nodule within the tail of the pancreas and is commonly mistaken by imaging studies as a neuroendocrine tumor. We report three cases of intrapancreatic accessory spleen diagnosed by endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) biopsy. Imaging studies showed well-circumscribed nodules in the tail of the pancreas. Two lesions were clinically suspicious for pancreatic neuroendocrine tumors and one appeared to be a cyst. EUS-guided FNA revealed predominantly small lymphocytes with a subset of histiocytes, conspicuous eosinophils, and plasma cells. There was also characteristic CD8 positive immunostaining of endothelial cells in cell block sections. We report the first series of accessory spleen in the pancreas diagnosed by EUS-guided FNA with the aid of CD8 immunostaining of splenic sinus endothelial cells.
authors.affiliation: Department of Pathology, Oregon Health and Science University, Portland, Oregon, USA.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Schreiner
authors.forename: Atiya
authors.initials: A
authors.lastname: Mansoor
authors.forename: Douglas O
authors.initials: DO
authors.lastname: Faigel
authors.forename: Terry K
authors.initials: TK
authors.lastname: Morgan
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D016827:CD8 Antigens / Q000378:metabolism; D002828:Choristoma / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D019160:Endosonography; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D010182:Pancreatic Diseases / Q000175:diagnosis* / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000473:pathology*; D013154:Spleen
chemical_list: D016827:CD8 Antigens