Unusual fate of vesicoallantoic cyst with non‐visualization of fetal urinary bladder in a case of patent urachus

Abstract

We present the sonographic findings of a fetus with a vesicoallantoic cyst. The cyst was first identified at 17 weeks of gestation; it was associated with an omphalocele, and disappeared spontaneously at 29 weeks. The fetal urinary bladder was not visualized thereafter. An omphalocele and exstrophia of the urachus were found at birth and repaired. Non-visualization of the fetal urinary bladder suggested rupture of the covering membrane of the omphalocele and allantois during fetal life. A defect in the wall of the omphalocele supported our hypothesis.

A Case of Fetal Vesicoallantoic Cyst in the Umbilical Cord

“…In 1 previously reported case [2], the fetal bladder became invisible on ultrasonography similar to our case; this suggests a connection between the cystic lesion and the fetal bladder. In previously reported cases of vesicoallantoic cyst which did not disappear at the time of labor, in only 1 case was the infant delivered vaginally [9]; in the remaining cases, cesarean section was selected for delivery [2,4,5,8,10,11] (table 1). We selected vaginal delivery because the ruptured cyst in the umbilical cord would not impede delivery.…”

“…In several previously reported cases, the vesicoallantoic cyst spontaneously disappeared before labor [2,[4][5][6][7][8] (table 1). In the majority of these cases, the cyst disappeared at approximately 30 weeks of gestation.…”

“…If the allantois fails to be obliterated, a single communicating cavity between the fetal urinary bladder and the allantois remains. The amount of fetal urine increases as fetal development proceeds and the fetal urine fills this cavity, resulting in the formation of a 'vesicoallantoic cyst' as a remnant of the extraembryonic portion of the allantois [2].…”

Prenatally diagnosed patent urachus with bladder prolapse

“…The cyst disappears around gestational week 22 to 32 according to the present and previous reports. [2][3][4][5][6][7][8][9][10]. The cyst probably ruptures as urine output increases and with development of the fetal abdominal wall.…”

Prenatal vesico-allantoic cyst outcome - a spectrum from patent urachus to bladder exstrophy

“…The degree of prolapse has been so severe in some cases that some authors identify the defect as an exstrophy variantsuperior vesical fissure or superior vesical fistula. 5,6 As in our case series, most newborns with vesico-allantoic cyst do not have splitting of Table 1 Various descriptors for vesico-allantoic communication Allantoic cyst [7][8][9] Vesico-allantoic cyst [10][11][12][13] Umbilical cord cyst 4,5,[14][15][16] Pseudocyst of umbilical cord [17][18][19] Bladder prolapse through patent urachus [20][21][22] Patent urachus cyst/urachal cyst 9,13,[23][24][25] Omphalocele and umbilical cord cyst 15 Small omphalocele with umbilical bladder evagination 26-28 Figure 1 Representative ultrasound image from second trimester presentation. Note the hourglass-shaped communication between the thicker intracorporeal bladder and thin, cystic allantoic component the abdominal wall musculature, the boney pelvis or genitalia, or abnormalities of the bladder neck/continence mechanism.…”