Peritoneal deciduosis mimicking peritoneal Carcinomatosis: A case report

Highlights • Deciduosis is defined as the presence of decidual tissue in an ectopic location. • It is caused by progesterone-mediated metaplasia of mesenchymal cells. • We describe a case of a non-pregnant patient with extensive peritoneal spread. • As in this report, this entity might mimic oncological conditions.
Ectopic decidual reaction (or deciduosis) can be rarely seen in the peritoneum and most of the cases in the literature are associated with pregnancy. It is more commonly found in the ovaries, uterus and cervix. Although its pathophysiology is not totally understood, it is accepted that peritoneal deciduosis develops as a result of the progesterone induced metaplasia of subserosal stromal cells during pregnancy. It is important to distinguish this entity from oncologic conditions, namely metastatic carcinoma and mesothelioma. We report an unusual case of a 40 year-old non pregnant patient that presented with imaging findings suggestive of peritoneal carcinomatosis.