Twin-twin transfusion syndrome presenting as polyhydramnios in both fetuses secondary to spontaneous microseptostomy

Abstract

The presence of polyhydramnios and oligohydramnios is pathognomonic for twin-twin transfusion syndrome (TTTS). However, polyhydramnios of both twins can exist in TTTS in the setting of a septostomy of the dividing membrane. In prior reported cases of dual polyhydramnios TTTS, the septostomy was identified through either ultrasound or fetoscopy thus helping to establish the diagnosis of TTTS with an unusual presentation. The presented case is a set of monochorionic, diamniotic twins who presented initially with dual polyhydramnios. Subsequent ultrasound and clinical and pathologic findings were otherwise consistent with TTTS. Unlike prior reported cases, a septostomy of the dividing membrane was never identified with ultrasound or even on post delivery placental examination. However, microseptostomies were demonstrated due to the transfer of indigo carmine between the amniotic sacs at amniocentesis. Thus in the setting of TTTS concern, the diagnosis should be considered with dual polyhydramnios even if a septostomy cannot be identified.

Keywords: microseptostomy; monochorionic; multifetal gestation; polyhydramnios; twin-twin transfusion syndrome.

Fig. 1

(A) The amniotic fluid of twin A was initially noted to be clear, though indigo carmine was injected into the sac at the conclusion of the procedure. However, (B) indigo carmine was present in the amniotic fluid of twin B during the amniocentesis for that twin, as evidenced by the color, demonstrating the presence of a microseptostomy despite no gross communication being present either on ultrasound or even pathologic evaluation of the membranes postdelivery.