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DECIDUAL SEPTAL
CYSTS |
Placental septa are supporting structures composed of decidual cells and
fibrinoid extending from the decidual floor of the placenta toward the
chorionic surface. The septa strengthen the placenta by partially subdividing
the intervillous space. The septa may contain fibrin deposits and atrophic
placental villi.
ETIOLOGY |
- Degeneration of the central decidual cells result in the formation of a cavity filled with homogeneous, fibrinous fluid (Decidual cyst).
- Hemorrhage into the cavity may resemble an intervillous thrombosis.
- Hemorrhage may compress adjacent villi, which may become necrotic and be confused with villous infarction.
- In a pathologically correlated study, 20-40% of cystic or hypoechoic lesions were found to be decidual septal cysts (1).
- Present in approximately 10-20% of placentas from full term uncomplicated pregnancies.
- More common in edematous patients (diabetes mellitus, Rh incompatibility).
ULTRASOUND |
- Hypoechoic.
- Usually £3 cm (larger hypoechoic areas suggest other pathology).
- Within placenta or under the fetal plate.
- May be close to cord insertion.
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REFERENCES |
- Harris RD, Simpson WA, Pet LR et.al. Placental hypoechoic-anechoic areas and infarction: Sonographic-pathologic correlation. Radiology 1990;176:75-80.