Urorectal septum malformation sequence: ultrasound correlation with fetal examination

Clinically diverse and perinatally lethal syndromes with urorectal septum malformation sequence

Urorectal septum malformation sequence (URSMS) is characterized by a spectrum of anomalies of the urogenital system, hindgut and perineum. It is presumed to be a constellation of an embryonic defect. Herein, we analyzed the clinically diverse syndromes associated with URSMS in our perinatal evaluation unit. We reviewed fetuses with URSMS in referrals for perinatal autopsy over a period of 3 years. Chromosomal microarray and genome sequencing were performed whenever feasible. Literature was reviewed for syndromes or malformations with URSMS. We ascertained URSMS in 12 of the 215 (5%) fetuses. Nine fetuses (75%) had complete URSMS and remainder had partial/intermediate URSMS. Eleven fetuses had malformations of other systems that included: cerebral ventriculomegaly; right aortic arch with double outlet right ventricle; microcephaly with fetal akinesia deformation sequence; ventricular septal defect and radial ray anomaly; thoraco-abdominoschisis and limb defects; myelomeningocele; spina bifida and fused iliac bones; omphalocele; occipital encephalocele; lower limb amelia and cleft foot. We report on six fetuses with recurrent and five fetuses with unique malformations/patterns where URSMS is a component. Exome sequencing (one family) and genome sequencing (eight families) were performed and were nondiagnostic. Additionally, we review the literature for genetic basis of this condition. URMS is a clinically heterogeneous condition and is a component of several multiple malformation syndromes. We describe several unique and recurrent malformations associated with URSMS.

Prenatal sonographic diagnosis of urorectal septum malformation sequence and chromosomal microarray analysis: A case report and review of the literature

INTRODUCTION

Urorectal septum malformation sequence (URSMS) is a rare congenital abnormal syndrome that is caused by the incomplete division of the cloaca. Based on whether the cloaca membrane breaks down or not, the URSMS are classified as full and partial forms. The prenatal diagnosis of URSMS remains challenging because of poor recognition to this malformation and the relatively non-specific sonographic features. We report a prenatally sonographic diagnosed case of the partial URSMS, and review the literature to summarize the prenatal features.

CASE REPORT AND REVIEW

A 37-year old woman was referred at 24 weeks of gestation for fetal abdominal cyst. Detailed sonographic examination was done and revealed the vesicocolic fistula, distended colon, absence of perianal hypoechoic ring, pyelectasis, and small stomach bubble. The URSMS was suspected.Amniocentesis was done and karyotyping revealed 46,XY. Furthermore, chromosomal microarray analysis (CMA) was performed for the first time in URSMS and an alteration of 111.8Kb deletion was detected in 16p13.3 which was located inside the RBFOX1 gene. Parental studies showed that the deletion was inherited from the father who has nomal clinical phenotype.The woman elected to terminate the pregnancy at 25 weeks gestation and postmortem examination confirmed the diagnosis of partial URSMS.The published studies were reviewed and 28 cases of URSMS with conducted prenatal ultrasonography were collected in this report. The most common sonographic description, as suspicious signs of URSMS, were severe oligohydramnios or anhydramnios, urinary tract anomalies, fetal intra-abdominal cysts, and dilated bowel. Also, enterolithiasis and vesicocolic fistula were relatively infrequent but highly specific feature of URSMS.

CONCLUSIONS

URSMS is difficult to be diagnosed prenatally. However, it has characteristic features that can be detected by fetal ultrasonography, and a precise prenatal sonographic examination is crucial for diagnosing URSMS. Besides, more genomic profiling studies are needed to elucidate the causality.

Spectrum of urorectal septum malformation sequence

Urorectal septum malformation sequence (URSMS) is a rare spectrum of malformations involving various organ systems. Here, we present eight cases of URSMS, noted in autopsy, with different degrees of complexity, seven being the complete type and one being the partial type. All cases had gastrointestinal tract malformation in the form of the imperforate anus and indeterminate genitalia. Other gastrointestinal tract anomalies were anal agenesis in two cases, anorectal agenesis in two cases, and malformed lower intestinal tract in four cases. The associated renal abnormality was noted in five cases, which were unilateral renal agenesis, dysplastic kidney, hydronephrosis, horseshoe kidney, and unilateral hypoplastic ectopic kidney. External genital malformation, present in both male and female fetuses, included a knob-like structure at perineum in female fetuses, genital fold hypoplasia and penile aplasia or hypoplasia in male fetuses. Skeletal abnormalities included two cases of sacral agenesis and one case of lumbosacral dysraphism. Other anomalies included a case with alobar holoprosencephaly, truncus arteriosus with hypoplastic lungs in one case, and three cases with abdominal wall defects. It is our attempt to delineate a spectrum of abnormalities associated with URSMS.

Cloacal dysgenesis sequence with bilateral renal agenesis and normal pulmonary development in twin pregnancy

Cloacal dysgenesis sequence (CDS) is a rare congenital anomaly. It is characterised by a smooth perineum with absence of anal and genitourinary orifices, with reported incidence of 1:50,000-250,000 births. Association with bilateral renal agenesis is still rarer and resultant severe oligohydramnios is associated with pulmonary hypoplasia. Only a few cases of CDS with bilateral renal agenesis have been reported in the English language literature, with associated pulmonary hypoplasia as a default phenomenon. We report a case of CDS and bilateral renal agenesis without associated pulmonary hypoplasia in a twin pregnancy, which, to the best of our knowledge, is the second reported case of this amalgamation.

What does fetal autopsy unmask in oligohydramnios?

OBJECTIVE

We aimed to determine the value of autopsy in fetuses with antenatally diagnosed oligohydramnios.

PATIENTS AND METHODS

We evaluated all fetal losses over a period of 6.5 years. Those with oligohydramnios on antenatal scan were critically analyzed. Oligohydramnios was defined as amniotic fluid index of less than five objectively or as an obvious lack of liquor at subjective assessment. A detailed postmortem examination was carried out in all the fetuses after obtaining an informed consent.

RESULTS

Fetal autopsy was conducted in 255 cases. Fifty-five (21.5%) fetuses were diagnosed to have oligohydramnios on antenatal ultrasonography. On analysis of antenatal causes of oligohydramnios, maternal/placental factors were noted in 18%, ultrasound findings known to affect amniotic fluid in 27% while cause remained unidentified in 54.5% of cases. On autopsy, fetal malformations were noted in 61.8% cases, intrauterine growth retardation in 21.8% fetuses and no obvious malformations in 16.3% fetuses. Renal anomalies were noted in 40% cases and non-renal malformations in 21.8% cases.

CONCLUSION

The postmortem examination helped us to identify the cause of fetal loss in 46 (83.6%) fetuses with antenatal oligohydramnios. A working diagnosis could not have been established without autopsy in 19 (34.5%) cases.

Long-term survival with cloacal dysgenesis sequence

Cloacal dysgenesis sequence (CDS) is a rare and lethal malformation. We report such a case of long-term survival, currently to 12 years of age. In the fetal period, she received a timely placement of vesico-amniotic shunt for a megabladder due to a severe urethral obstruction. Postnatally, cystostomy and colostomy were created because of no perineal opening of urethra, vagina, and anus. Anorectoplasty, construction of efferent conduit, and colostomy closure were performed at 4 years of age. Ileovaginoplasty and ileovesicostomy which was a Mitrofanoff-type of conduit, and labioplasty were performed at the age of 11 years. To the best of our knowledge, only five survivors with CDS over 1 year of age have been reported.

Comparison of prenatal ultrasound findings and autopsy findings in fetuses terminated after prenatal diagnosis of malformations: an experience of a clinical genetics center

OBJECTIVE

To compare antenatal diagnosis with post mortem examination findings in the pregnancies terminated after prenatal detection of anomalies and to evaluate the potential benefits of post mortem examination for counseling regarding the risk of recurrence.

METHODS

This is a retrospective study over a 7-year period from 2001 to 2007. Pregnancies terminated after prenatal identification of fetal malformation were evaluated by post mortem examination of 91 fetuses.

RESULTS

Fetal autopsy provided a definite diagnosis in 72/91 (79.1%) of the cases. Fetal autopsy confirmed the sonographic findings in 89 of 91 cases (97.8%). In 66 (72.5%) cases there was complete concordance between prenatal and autopsy findings, while in 23 cases there was major concordance. There were 49 cases with isolated malformations, 41 cases with multiple (89) malformations, and, in one case, no malformation was found at autopsy. Of the 89 associated malformations, 39 (43.8%) were detected prenatally and 50 (56.2%) were detected on fetal autopsy. The additional malformations detected on autopsy included 38 major and 12 minor malformations Additional findings helped in redefining the diagnosis and the risk of recurrence in 30 of 91 (33%) cases.

CONCLUSION

The present study emphasizes the importance of autopsy in providing accurate etiologic diagnosis necessary for genetic counseling.

Urorectal septum malformation sequence: a report of seven cases

Urorectal septum malformation (URSM) sequence is an extremely uncommon anomaly. We report herein seven cases of URSM sequence that were identified after reviewing all autopsies conducted at our hospital over a period of 26 years (1981-2006). The URSM spectrum includes partial and full URSM sequences. Absent perineal and anal openings with ambiguous genitalia are included under 'full URSM sequence', and a single perineal or anal opening draining a common cloaca with an imperforate anus is called 'partial URSM sequence'. Of our seven cases of URSM, three were full URSM sequence and four were partial URSM sequence. Associated renal anomalies were found in all of the cases. Three cases had unilateral renal agenesis and one each had bilateral renal agenesis and bilateral renal dysplasia, respectively. The remaining two cases had unilateral renal agenesis with contralateral kidney showing features of cystic dysplastic kidney and renal hypoplasia, respectively. Congenital anomalies involving other organs were also found in some of the cases. The longest survival period in our series was 10 days, in accordance with the short survival period usually associated with URSM. Five of the patients were females, one was male, and the sex of one neonate could not be ascertained. One of the neonates was from a twin pregnancy; the other twin was normal.

Post-mortem examination of prenatally diagnosed fatal renal malformation

OBJECTIVE

Renal malformations can be associated with genetic syndromes and chromosomal disorders. Fetal autopsy including histopathological examination of kidney is important to arrive at definite diagnosis. The objective was to assess importance of fetal autopsy and histopathology.

STUDY DESIGN

Retrospective analysis of cases with fetal renal malformations was done. All fetuses terminated were examined with whole body radiograph, external and internal examination and histopathological examination.

RESULT

A total of 21 cases with renal malformations were studied. Of all 3 were of bilateral renal agenesis, 4 showed autosomal recessive polycystic kidney disease and 13 showed features of multicystic kidney. Three of these had hyperplasic-enlarged bladder and autopsy confirmed urorectal septum malformations in two cases and posterior urethral valve in one case. One case had associated malformations like encephalocele that suggested diagnosis of Meckel-Gruber syndrome and another had associated lateral body wall defect. In five cases kidney was hypoplastic suggestive of Potter type IIa.

CONCLUSION

Ultrasound is an effective diagnostic modality; however fetal autopsy after termination of pregnancy is important to arrive at a definitive diagnosis. It's important to distinguish between autosomal recessive polycystic kidney disease (ARPKD) and cystic dysplastic kidney as recurrence risk is 3% in case of cystic renal dysplasia in contrast to 25% in case of ARPKD. Gross examination may point toward syndromic diagnosis like Meckel-Gruber syndrome; hence mode of prenatal diagnosis may vary in subsequent pregnancies.

Urorectal septum malformation sequence: prenatal progression, clinical report, and embryology review

The urorectal septum malformation sequence (URSMS) is characterized by severe abnormalities of the urorectal septum (URS) and urogenital organs. The primary defect in this condition appears to be a deficiency in caudal mesoderm leading to the malformation of the URS and other structures in the pelvic region. Recent clinical reports discuss prental findings of URSMS [Lubusky et al. (2006); Prenatal Diagnosis 26: 345-349]. However, here we present a case of URSMS with prenatal findings not previously described, review the literature on URSMS, and summarize current embryological understanding of the pathology seen in hindgut development. The unique prenatal finding in the patient was an abdominally located cystic mass that was first seen at 18 weeks of gestation. Over the next 6 weeks, the mass decreased in size until it disappeared. Concurrent with reduction of the cyst, ascites developed. The patient displayed several traditional URSMS indicators including abnormal bladder and dysplastic kidneys. Our findings give additional insight into the embryology of urorectogenital development. Specifically, they suggest that the cystic mass may have been a persistent urachus prior to septation of the cloaca. Postnatal evaluation confirmed a URSMS diagnosis; the newborn had ambiguous genitalia, hypoplastic kidneys, absent uterus, imperforate anus, smooth perineum, and overall underdeveloped urogenital structures.