Acinar Cell Carcinoma, Pancreatic

Acinar cell carcinoma is a malignant epithelial tumor with acinar differentiation. It is uncommon, accounting for 1–2% of all exocrine pancreatic tumors. These tumors tend to reach a large size at presentation and frequently have multiple areas of hemorrhage and necrosis or cystic degeneration. Typical microscopic findings include a gross lobulation of markedly cellular tissue by fibrous strands. In most tumors acinar areas alternate with trabecular and solid formations. A capsule often surrounds these tumors. Vascular infiltration and other adjacent structures invasion are frequent. Typical clinical presentation is related to increase of lipase and includes subcutaneous fat necrosis, rash, polyarthralgias, and eosinophilia. An association with elevated serum alpha‐fetoprotein and carcinoembryonic antigen levels has been reported, a unique feature among the pancreatic exocrine tumors. At imaging, most of these tumors appear as a well circumscribed, homogenous or heterogeneous mass...