Ectopic decidual reaction – A diagnostic dilemma

Abstract

The occurrence of decidualization outside the endometrium, is called as ectopic decidual reaction. It can involve any abdominal organs, such as ovary, fallopian tube, cervix, uterine surface, omentum, etc. and present as grey white nodules. These nodules grossly mimic metastatic disease and granulomas, causing a diagnostic dilemma. Decidual reaction is a benign condition and can regress spontaneously in the postpartum period. Thus, it is important to accurately diagnose these lesions for optimal treatment. Histologic examination followed by immunohistochemistry can be performed on the biopsies sampled during cesarean sections, tubal ligation, appendectomy, etc. to obtain a correct diagnosis. Peritoneal location of ectopic decidua is less frequent and can be an incidental finding. Few patients may present with the symptoms of abdominal pain, hemorrhage or irritable bowel syndrome. We thereby, report a case of peritoneal ectopic decidual reaction and discuss its histopathological features, immunohistochemistry and the differential diagnosis.