title: [Ectopic Decidualization: A Forgotten Entity].
abstract: BACKGROUND
  Although ectopic decidualization is an entity often underdiagnosed, it may have adverse clinical impact on maternal-fetal morbimortality. The objective of this study was to review the scientific evidence regarding the etiology, clinical features, diagnosis and therapeutic approach on this issue.
  
  
  METHODS
  The search for this literature review was conducted in PubMed, Web of Science and Scopus, through the query ('deciduosis' OR 'ectopic decidualization' OR 'ectopic decidua' OR 'ectopic decidua reaction'), considering articles of all evidence levels published up to 31/06/2014.
  
  
  RESULTS
  Ectopic decidualization is, usually, a benign condition, asymptomatic and does not require therapeutic intervention. It occurs mostly during pregnancy, with complete regression in the postpartum period. The frequency of the diagnosis depends on the clinical suspicion and its location, being the omentum and the ovary the most common sites. When symptomatic, the main clinical manifestations are genital bleeding and hemoperitoneum. Differential diagnosis includes malignant disease and histopathological confirmation is essential in these situations. The low index of suspicion may lead to a biopsy, which can have serious adverse outcomes due to the high friability of these lesions.
  
  
  CONCLUSIONS
  The recognition of this entity and its clinical features are essential for the management of these patients. On one side this allows an early and proper medical approach in severe cases, on the other side (the majority of cases) maintaining an expectant attitude avoiding iatrogeny, does not compromise, in most cases, the favorable outcome of ectopic decidualization.
authors.affiliation: Faculdade de Medicina. Universidade do Porto. Porto. Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Mendes
authors.affiliation: Serviço de Ginecologia e Obstetrícia. Centro Hospitalar São João. Porto. Portugal. Departamento de Ginecologia e Obstetrícia. Faculdade de Medicina. Universidade do Porto. Porto. Portugal.
authors.forename: Antónia
authors.initials: A
authors.lastname: Costa
mesh_terms: D002828:Choristoma / Q000473:pathology*; D003656:Decidua; D005260:Female; D006801:Humans; D009852:Omentum; D049590:Postpartum Period; D011247:Pregnancy