Three-dimensional pattern of ductuloacinar associations in normal and pathological human pancreas.

To explain the changes that must occur to produce the characteristic lesions of chronic calcifying pancreatitis, a three-dimensional reconstruction of pancreatic ductules and acini has been undertaken in normal subjects and in patients presenting with disease. This has been done with 3-micron serial sections of tissue embedded in plastic. Two approaches were used. In the first, ductules were reconstructed along with the acini directly associated with them. Using this method, adhesions or anastomoses between acini were not evident in normal specimens, and the quantity of acini associated with the ductules seemed small. The second method involved tracing the association of acini and ductules, beginning in the periphery of lobules, with the aid of a drawing tube. It became evident that an acinus was not necessarily the termination of the glandular system, but that intercalated ducts could be formed on the other side of the acinus, extending the quantity of acinar contributions that could be made to a primary ductular system. Evidence of dilation of ducts, atrophy of acini, formation of cul-de-sacs, and localized obstruction were found by three-dimensional reconstruction of serial sections from patients with chronic pancreatitis along with anastomosis between acini. It is probable that anastomosis becomes more detectable in patients as duct lumina enlarge. Anastomoses in the ductules in chronic pancreatitis may result from loss of some lobular structures, emphasizing preexisting connections or fusions of pancreatic elements, or both, as part of the pathological process.