Pancreatic pathology in trisomy 13: specificity of the morphologic lesion.

Pancreases from 8 patients with trisomy 13 were studied. Ectopic splenic tissue was present in 6: 3 had accessory spleens and ectopic splenic tissue embedded in the pancreas, one had intrapancreatic splenic tissue without an accessory spleen, and one had an accessory spleen without intrapancreatic splenic tissue. The intrapancreatic splenic tissue was multiple, generally poorly or nonencapsulated, and contained pancreatic acini, islets of Langerhans, and ducts lined by tall columnar epithelium with goblet cells. The rest of the pancreas in these and other cases of trisomy 13 had microcyst formation and focal proliferations of small ducts similar to those seen in the splenic tissue. This constellation of features appears to be distinctive of trisomy 13.