Ultrastructural studies of human acute pancreatitis.

The pancreatic tissue from a patient with acute hemorrhagic necrotizing pancreatitis was studied by routine electron microscopic observation. The remarkable change was the destruction of pancreatic acinar units. 1) The acinar lumen was dilated with filling of fibrillar materials, which occasionally contained degenerated cellular components or neutrophils. 2) Accumulations of fibrillar materials were present at the periphery in the acinar cells, especially depositted thickly at the basal portion. 3) In some acinar cells, the accumulation of fibrillar materials occupied the entire acinar cell, accompanied by disappearance of luminal margin, and the intracellular fibrillar materials were mixed with acinar lumen contents. 4) The acinar units which showed above described changes had almost intact basal lamina.