To the Editor.—We read with great interest the report by Bennion et al in the October 1988 Archives.1 However, we feel that a fourth category of agenesis of the gallbladder exists; namely, those cases where absence of the gallbladder is associated with symptomatic or asymptomatic congenital anomalies of the same developmental system. This is illustrated by the occurrence of several cases of congenital absence of the gallbladder in which these pancreatic anomalies were found: congenital agenesis of the pancreas2 and annular pancreas.3,4
The relevance of this fourth category exists in the "embryological traffic jam" at the duodenal region when the liver, biliary system, and pancreas develop. Special attention to the association of congenital malformations in this region can provide better understanding of their embryogenesis.
In view of the references mentioned above that are not cited by Bennion et al, we suggest that more than 381 cases