Aberrant acinar cell CA 19-9 expression and peri-insular acinar cell alterations in an adult human pancreas

We herein report on a 23-year-old female patient who suffered from Crohn's disease and anorexia nervosa and died after long-term malnutrition and a perforated colitis. At autopsy, her pancreas displayed two peculiar findings. First, there was a constant and aberrant expression of CA 19-9 in the acinar cells. The expression of the carbohydrate antigen CA 19-9 is normally confined to duct-like epithelia, including centroacinar cells, while islet and acinar cells have repeatedly been reported to be immunohistochemically negative. Thus, to the best of our knowledge, our case is the first to show aberrant acinar CA 19-9 expression, and its potential meaning is discussed. Second, the pancreas showed a heterogeneity in acinar morphology, with peri-insular acini being considerably larger than tele-insular acini. The existence of enlarged peri-insular acini, mainly in animals, has occasionally been reported. Its origin, however, is still unclear. Some authors have proposed an influence of high insulin concentrations, exerted via the insulo-acinar capillary axis. We agree with the concept of an islet-derived mechanism. However, as we have observed a similar heterogeneity in streptozotocin- and autoimmune-diabetic rats, we presume that other islet hormones, in particular glucagon, might be more important for this phenomenon in the animals, as well as in the present case.