Decidual cyst: endovaginal sonographic sign of ectopic pregnancy.

Abstract

Patients with decidual cysts are at high risk for ectopic pregnancy and should be monitored or treated appropriately, depending on the clinical findings.

The History of Imaging in Obstetrics

“…From 6 weeks onward, dating is based on the crown to rump length (64). cyst (75). A number of studies from the early to mid-1980s assessed sonographic signs to help distinguish intrauterine gestational sacs from pseudogestational sacs.…”

Diagnostic Criteria for Nonviable Pregnancy Early in the First Trimester

“…18 Therefore, any round or oval fluid collection in a woman with a positive pregnancy test most likely represents an intrauterine gestational sac ( Fig. 21,22 The yolk sac, a circular structure about 3Y5 mm in diameter, makes its appearance at about 52 weeks of gestation. 21,22 The yolk sac, a circular structure about 3Y5 mm in diameter, makes its appearance at about 52 weeks of gestation.…”

Role of sonography in the diagnosis of ectopic pregnancy

“…22,23 A ''decidual cyst'' is a well-demarcated cystic structure within the endometrium that does not abut the endometrial canal and does not have echogenic trophoblastic ring, which helps to differentiate from intradecidual sign. [24][25][26] Embryologically, an early intradecidual gestational sac should abut the endometrial canal, whereas decidual cysts tend to appear away from the canal, often near the junction of the endometrium and myometrium 27 ( Figure 1). The pathogenesis of decidual cysts has not yet been determined, but as Ackerman et al 24 reported, they may represent an early breakdown of the decidua.…”

“…[24][25][26] Embryologically, an early intradecidual gestational sac should abut the endometrial canal, whereas decidual cysts tend to appear away from the canal, often near the junction of the endometrium and myometrium 27 ( Figure 1). The pathogenesis of decidual cysts has not yet been determined, but as Ackerman et al 24 reported, they may represent an early breakdown of the decidua. Decidual cysts appear to precede decidual cast formation, because in the Ackerman et al study none of the patients had a decidual cyst and a decidual cast simultaneously.…”

“…When the interstitial pregnancy is small, the interstitial line may represent the interstitial portion of the tube, whereas it may represent the endometrial canal when the gestation is larger. 24 In a few recent case reports, the use of 3-dimensional sonography has been reported to be useful in localizing EP when its exact location relative to the uterine cavity is unclear or difficult to determine, as in an interstitial pregnancy. 35 The diagnosis of an intrauterine pregnancy is virtually sufficient to exclude extrauterine pregnancy in emergency settings, because the possibility of heterotopic pregnancies, which occur with an incidence of 1/30,000, is negligible.…”