Prenatal Diagnosis of Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome in One Fetus of a Twin Pregnancy

Abstract

Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare genetic disorder that affects the muscle tone in the intestinal and urinary tract systems. Prenatal diagnosis is difficult because an identifiable genetic locus is absent and there are no specific ultrasound findings. We present an interesting case of this syndrome diagnosed prenatally in one fetus of a twin pregnancy. A 26-year-old white woman gravida 4, para 2103, at 11 weeks' gestation was diagnosed with a dichorionic diamniotic twin pregnancy. The patient's history was significant for having a previous female infant diagnosed with MMIHS. During a follow-up ultrasound at 26 weeks, one of the twins had multiple anomalies including: a pelvic cystic structure with a keyhole appearance, enlarged stomach, dilated bowel, and prominent renal pelves. Prenatal diagnosis of MMIHS can be possible on ultrasound findings with a positive family history.

Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome: Case Report and Review of Prenatal Ultrasonographic Findings

“…Difficulties in securing a correct prenatal diagnosis are largely attributable to the rarity of the condition and inconsistent and variable fetal presentations, which is supported by the findings of this review [20,21,22,23,24]. Prenatal sonographic findings associated with MMIHS were first reported by Vezina et al [25] to include a markedly enlarged fetal bladder, bilateral fetal hydronephrosis and polyhydramnios.…”

“…These abnormalities may be difficult to observe in association with MMIHS due to a massively enlarged fetal bladder. In this review, a dilated fetal stomach was usually detected in the early second trimester [4,22,24,30] and preceded findings of dilated bowel loops, which were usually apparent in the third trimester. The role of MRI in the setting of MMIHS is yet to be determined, however, and may offer additional information regarding gastrointestinal and genitourinary abnormalities [15,17].…”

“…While the data from this review indicate that prenatal diagnosis was successfully established in less than one third of reported cases, the presence of a previously affected sibling greatly facilitated correct diagnosis. In a few cases, the syndrome was correctly diagnosed based solely upon the combination of genitourinary and gastrointestinal findings [13,14,18,24]. Munch et al [17] described a successful prenatal diagnosis with a combination of ultrasonography and fetal MRI, which revealed additional gastrointestinal features (microcolon and dilated esophagus) not detected by ultrasound alone.…”

“…Bladder dimensions can become massive, extending into the abdomen and displacing the diaphragm. The ‘keyhole' sign, which represents a dilated proximal urethra and is more typical of a mechanical lower urinary tract obstruction presentation, has been described in approximately 8% of fetuses with MMIHS [14,24,26]. As such, it cannot consistently distinguish between obstructive causes of fetal megacystis and MMIHS.…”

Megacystis-Microcolon-Intestinal Hypoperistalsis Syndrome: A Case Report

“…Autosomal recessive transition has been defined in most publications which report family history and sibling cases [5–9]. The frequency of the disease is observed three or four times more in girls than in boys [4, 6, 10].…”