[Deciduosis of the appendix as cause of acute abdomen in pregnancy].

Ectopic decidua reaction or deciduosis is a physiological phenomenon of pregnancy due to a progesterone induced metaplasia of the pluripotential cells of the subcelomic mesenchyma. Usually it is an incidental finding that has not been associated with clinical symptoms. Isolated cases of ectopic decidua have been reported with symptoms simulating appendicitis. We are reporting a case of deciduosis localized in the appendix with abdominal pain during the last period of pregnancy.