Pancreatic acinar cell carcinoma extending into the common bile and main pancreatic ducts

Abstract

Acinar cell carcinoma (ACC) of the pancreas is relatively rare, accounting for only approximately 1% of all exocrine pancreatic tumors. A 69-year-old man was found to have a mass lesion measuring approximately 4 cm in diameter in the pancreatic head on ultrasound, abdominal dynamic CT, and percutaneous transhepatic cholangiography. Magnetic resonance cholangiopancreatography showed defect of the lower common bile duct (CBD) due to obstruction by the tumor cast. Histopathologically, the pancreatic head tumor invaded the main pancreatic duct (MPD) and CBD with extension into the CBD in a form of tumor cast. The tumor cells consisted of a solid proliferation with abundant eosinophilic cytoplasm and round nuclei in an acinar and trabecular fashion. A 55-year-old man with upper abdominal pain and nausea, had a cystic lesion approximately 3 cm in size in the pancreatic tail on CT. Histopathologically, the tumor was encapsulated by fibrous capsule and had extensive central necrosis with solid areas in the tumor periphery, and invaded with extension into the MPD in a form of tumor cast. The tumor cells resembled acinar cells in solid growths. Two resected cases of ACC with unusual tumor extension into the CBD and the MPD, respectively, are reported.

Pancreatic Ducts as an Important Route of Tumor Extension for Acinar Cell Carcinoma of the Pancreas

“…Recently, several cases of ACC with characteristic growth features have been reported, in which the tumors grew predominantly in the large pancreatic ducts [main pancreatic duct (Wirsung duct) or accessory pancreatic duct (Santorini duct)] and exhibited polypoid and/or papillary features. [1][2][3]15 Basturk et al 1 proposed a new variant of ACC showing a predominantly intraductal, papillary, and/or papillocystic growth pattern. This variant of ACC was suggested to be very rare, and to show more indolent behavior.…”

The utility of a novel antibody in the pathological diagnosis of pancreatic acinar cell carcinoma

“…Electron microscopic examination was performed for two cases and revealed zymogen granules in the cytoplasm 6. The remaining cases were diagnosed based on morphological and IHC analyses.…”

“…ACCs that show acinar cell differentiation have zymogen granules in the cytoplasm in general, and the presence of these zymogen granules has proven useful for pathological diagnosis. Traditionally, the diagnosis of ACCs has required periodic acid-Schiff (PAS) stain and diastase digestion PAS (dPAS) stain to confirm the presence of dPAS-positive granules in the cytoplasm,1 4 5 or electron microscopy to confirm the presence of zymogen granules in tumour cells 1 4 6. Recently, it has become possible to immunohistochemically demonstrate the presence of pancreatic enzymes in the cytoplasm 1 3 4 7…”

Nonfunctioning pancreatic endocrine tumor with extension into the main pancreatic duct: Report of a case

“…[9][10][11][12][13] The intraductal growth of PETs is considered very rare. 8 We describe a case of malignant NFPET, which proliferated extensively into the MPD, forming an intraductal lesion.…”