Ectopic decidua

Decidual cells found outside inner lining of the uterus are called ectopic decidual cells or ectopic decidua. This condition was first described in 1971 by Walker<ref>,

 Pregnancy related peritoneal ectopic decidua: Morphological and clinical evaluation, 
 Turkish Journal of Pathology, 
 
 Vol. 28(Issue: 1),
 pp. 56–60,
 DOI: 10.5146/tjpath.2012.01098,
 PMID: 22207433,</ref> and the name 'ectopic decidua' was coined by Tausig.<ref>, 
 Ectopic ovarian decidua without pregnancy, 
 American Journal of Pathology, 
 
 Vol. 33(Issue: 2),
 pp. 199–217,
 
 PMID: 13402883,
 PMC: 1934629,</ref> While ectopic decidua is most commonly seen during pregnancy, it rarely occurs in non-pregnant women, accompanied by bleeding and pain.

Generally, ectopic decidua has no clinical symptoms, but it sometimes manifests as abdominal pain in pregnancy.<ref>,

 Deciduosis of the Appendix Manifesting as Acute Abdomen in Pregnancy, 
 Acta Chirurgica Latviensis, 
 
 Vol. 14(Issue: 1),
 pp. 43–45,
 DOI: 10.2478/chilat-2014-0110,
 
 
 
 Full text,</ref> Ectopic decidua most commonly occurs the ovary, cervix and serosal lining of the uterus. It rarely occurs in peritoneum also. In the peritoneum, ectopic decidua is formed due to metaplasia of subserosal stromal cells under the influence of progesterone. It regresses within 4–6 weeks after childbirth. Therefore, no treatment is needed for this condition. However, it is necessary to differentiate deciduosis from metastatic cancers and mesothelioma.