Deciduosis of the appendix as cause of abdominal pain in pregnancy.

Ectopic decidua reaction or deciduosis is a physiological phenomenon of pre gnancy 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 deci dua have been reported with symptoms simulating appendicitis. We are report ing a case of deciduosis localized in the appendix with abdominal pain duri ng the last period of pregnancy.