Alpha fetoprotein-producing acinar cell carcinoma of the pancreas showing multiple lines of differentiation

Abstract

An alpha fetoprotein (AFP)-producing tumour occurring in the head of the pancreas of a 30-year-old woman is reported. Histological examination revealed a markedly solid proliferation of tumour cells with prominent nucleoli and occasional luminal structures, some of which contained mucinous material stained with mucicarmine and alcian blue. No squamoid corpuscles were recognized. Immunohistochemistry showed intense positivity for lipase trypsin, and AFP basically, and single cells were also positive for carcino-embryonic antigen, CA19-9, synaptophysin and neuron-specific enolase. Pancreatic hormone-positive cells were absent. Electron microscopical examination revealed numerous granules of variable sizes in the tumour cells, which were considered to be zymogen. The tumour is an acinar cell carcinoma with multi-directional differentiation including the ability to produce AFP. Among AFP-positive pancreatic tumours, acinar cell carcinoma and pancreatoblastoma seem to be the most frequent.

SALL4 is expressed in pancreatic acinar cell carcinoma

“…AFP is produced in the liver, yolk sac, and in the fetal gastrointestinal tract [28] . Thus, tumors originating from these tissues may show AFP production [24] as seen in one case in this report.…”

“…Exocrine and endocrine pancreatic cells develop from a common endodermal epithelium, and human tumors may mimic the relationship between ducts and islet cells during early developmental stages [23,24] . ACCs are thus capable of differentiating into ductal and neuroendocrine components.…”

“…ACCs are thus capable of differentiating into ductal and neuroendocrine components. Pancreatic tumors composed of all three components of acinar, ductal, and islet cells have been reported [24,25] . Klimstra et al 1994 proposed the term "mixed acinar-endocrine carcinoma" in ACCs with more than 25% of the tumor cells exhibiting endocrine features.…”

Nonductal neoplasms of the pancreas

“…AFP has been detected by immunohistochemistry in acinar cell carcinomas in patients with and without elevated serum AFP. [105][106][107][108]116 Ultrastructural examination of acinar cell carcinomas 78,117-122 reveals abundant rough endoplasmic reticulum and mitochondria. The cells rest on a basement membrane and have well-developed lumina.…”

Liver stem cells: when the going gets tough they get going

“…Similarly, cultured rat pancreatic ductal epithelial cells can undergo hepatocytic differentiation when transplanted subcutaneously or intraperitoneally into syngeneic rats (Chen et al 1995). Furthermore, pancreatic acinar cell carcinomas expressing a combination of hepatocyte, intestinal and neuroendocrine markers have been found in man (Shinagawa et al 1995), and hepatocyte differentiation can occur in adenocarcinomas of the renal pelvis (Ishikura et al 1991) and stomach (Ishikura et al 1986). The hepatoid stomach adenocarcinomas express a number of hepatocytespecific markers, and in one case even bile secretion was evident (Ishikura et al 1986).…”