Endoscopic ultrasound-guided fine needle aspiration cytology of intraductal papillary mucinous tumor of the pancreas. A case report

BACKGROUND: Intraductal papillary mucinous tumor (IPMT) of the pancreas is a recently proposed pancreatic tumor entity with a peculiar clinical and pathologic profile. It presents with symptoms that are mostly attributed to the mass effect of the tumor. However, a long history of diabetes mellitus and/or chronic pancreatitis is usually noted. It is thought that IPMT has better prognosis than the usual pancreatic ductal adenocarcinoma and its early identification is important. On imaging studies these neoplasms appear usually as multiloculated, cystic tumors that cannot be easily differentiated from other cystic pancreatic neoplasms. CASE: A 73-year-old, white woman with recent symptoms related to bile duct obstruction and diabetes mellitus and a long history of "chronic pancreatitis" was found to have a pancreatic mass on computed tomography. Endoscopic ultrasound-guided fine needle aspiration of the pancreatic mass and dilated pancreatic duct was performed. Cytopathologic examination of the aspirated material revealed large cells with abundant, eosinophilic cytoplasm arranged singly or occasionally in large sheets with complex papillary fragments. Occasional goblet cells or cells with cytoplasmic mucin-containing vacuoles were also noted within the tumor tissue fragments. The nuclei were large, with nuclear size variability and prominent nucleoli. Copious amounts of mucin and numerous muciphages were noted in the background. A diagnosis of "cystic mucinous tumor, cannot rule out invasion," was entertained. The patient underwent partial pancreatectomy. The histologic features of the resected specimen were consistent with IPMT, with focal areas suggestive of early stromal invasion. CONCLUSION: The cytologic features encountered in the aspirate of this tumor are highly suggestive of IPMT and can help differentiate it from other pancreatic tumors with mucin production, such as the classic mucinous cystic neoplasm and the more common ductal carcinoma.