Lipid-rich variant of pancreatic endocrine neoplasms: a case report.
BACKGROUND
Pancreatic endocrine neoplasms (PENs) are a well-defined and well-characterized group of tumors. We report a rare variant of PENs called a lipid-rich variant and elaborate on its cytologic features with reference to fine needle aspiration (FNA).


METHODS
The patient was a 74-year-old man with a 2.1-cm mass in the body of the pancreas. The FNA showed numerous cells with vacuolated, foamy cytoplasm, mostly arranged individually but also in some apparently cohesive clusters. The nuclei were quite uniform. Many of the cells had the appearance of histiocytes. The cells in the cell block were immunoreactive (positive) for cytokeratin AE1/AE3, synaptophysin, and chromogranin A. Some admixed histiocytes stained for CD68. A diagnosis of PEN was made, with a suspicion for lipid-rich variant. An elective resection of the tumor was performed, which confirmed the diagnosis of lipid-rich variant of PENs. Lipid-rich variant of PENs can present a diagnostic dilemma on FNA.


CONCLUSIONS
Its mimickers include adrenal cortical carcinoma, metastatic clear-cell renal cell carcinoma, clear-cell PEN, foamy gland pattern of pancreatic ductal carcinoma, solid pseudopapillary tumor, and acinar cell carcinoma. The distinguishing morphologic and immunohistochemical features of each are described.
Department of Pathology and Laboratory Medicine, Danbury Hospital, 24 Hospital Avenue, Danbury, Connecticut 06810, USA. salman.ayub@danhosp.org
Salman B
SB
Ayub
Jessica
J
Dodge
D000368:Aged; D044963:Biopsy, Fine-Needle; D053379:Chromogranin A / Q000378:metabolism; D004701:Endocrine Gland Neoplasms / Q000473:pathology*; D006644:Histiocytes / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007430:Intraoperative Care; D008055:Lipids / Q000737:chemistry*; D008297:Male; D010179:Pancreas / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000473:pathology*; D013194:Staining and Labeling; D014617:Vacuoles / Q000473:pathology
D053379:Chromogranin A; D008055:Lipids