| Pancreatic Pathology Online
Pathology of Acinar Cell Carcinoma of the Pancreas
Dr Sampurna Roy MD June 2016
carcinomas (ACCs) are rare malignant tumours of the exocrine pancreas.
Acinar cell carcinoma accounts for about 1-2% of pancreatic exocrine tumours.
The specific molecular alterations that characterize Acinar cell carcinomas have not yet been elucidated.
Acinar cell carcinomas are morphologically and genetically distinct from the more common pancreatic ductal adenocarcinomas.
Instead, the morphological, immunohistochemical, and clinical features of Acinar cell carcinomas overlap with those of another rare pancreatic neoplasm.
It occurs mainly in adult males (rarely in children and adolescents).
In adults the tumour behaves like ductal adenocarcinoma such as early death, widespread metastases to regional lymph nodes, liver and lungs.
In children prognosis is more favorable.
Acinar cell carcinoma has been reported in association with the following conditions:
Multifocal fat necrosis (subcutis, bone marrow and abdomen).
Non-bacterial thrombotic endocarditis. Cardiac Path Online
The tumour arise from any part of pancreas as large (2-15 cm in diameter), well demarcated, soft, lobulated masses with a fleshy to yellow colour.
Necrosis, or hemorrhage, invasion into adjacent structures (duodenum, stomach or spleen) and cystic change is often present.
Microscopically, the tumour infiltrates pancreatic tissue.
The growth pattern may be acinar (microglandular), trabecular, solid, or mixed with plenty of thin walled blood vessels.
Well differentiated cells are round, monomorphic, medium to large size with abundant eosinophilic, fairly granular and PAS-positive, diastase resistant zymogen granules.
Nuclei are uniform, round, large with conspicuous nucleoli. Mitoses are frequent.
The tumour is positive for lipase, trypsin, chymotrypsin and alpha1-antitrypsin.
Amylase and CEA are rarely positive in some cases.
Scattered tumour cells show positive staining for neuroendocrine markers (chromogranin and synaptophysin).
Electron microscopic findings:
Zymogen granules are present in the neoplastic cells.
Neuroendocrine tumours (greater cytological uniformity and PAS- negative) should be distinguished from acinar cell carcinoma.
Acinar cell cystadenocarcinoma is a rare cystic variant of acinic cell carcinoma.
Focal acinar cell dysplasia has been reported in surgical specimens and in postmortem cases. No convincing acinar cell adenoma has been recorded.
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