This fetus had an abnormal alpha-fetoprotein. These are 4 representative images. The first image is at the front of the abdomen, the second a section of the spine, the third a section at the level of the perineum and the last... well that one you know!

Question: What is the name of this condition ?

Findings

The first 2 images had very clear findings. The first represented an omphalocele, the second a neural tube defect. The fourth picture was a clear clubfoot.

What about the 3^rd image ? Well we knew it was at the level of the perineum. All we can say is that there is not much identifiable there, except maybe something that might resemble labias, and some lumpy-bumpy structure. What is noticeable too is the absence of bladder ! Well, all together, there are not many perineal masses. Since this does not look much like a sacrococcygeal teratoma, the best candidate is a lesion like bladder/cloacal extrophy.

To recapitulate: this is a baby that has:

1. An omphalocele
2. A bladder/cloacal extrophy
3. A neural tube defect
4. Plus a bonus clubfoot !

The association of 3 large anomalies in the same region (the caudal midline) is highly suggestive of a midline filed defect and thus a syndrome that associate all three is what we should recognize. If you do not recognize that specific condition from these 3 anomalies, introducing these keywords in OMIM or Medline brings the diagnosis:

OEIS complex.

Introduction

The cloaca, constitutes a functional definitive organ in the pre-mammals like batrachians, reptiles and birds. In humans, it represents a temporary embryonic structure where the genital, urinary and digestive systems join caudally. Its correct development gives origin to the lower abdominal wall, bladder, intestine, anus, genitals and also part of the pelvis bones and lumbosacral spine. Deviation of the normal development of the cloaca causes a series of phenotypes the most severe expression of which is the OEIS complex (Omphalocele-Exstrophy-Imperforate anus-Spinal defect).

Synonyms: cloacal exstrophy, vesicointestinal fissure, splanchnic exstrophy and exstrophy -epispadias sequence.

Clinical presentation.

This 29-year-old G4P3 patient with no pathological antecedents had spotty prenatal care. She was referred to our unit for perinatal evaluation with the diagnosis of spina bifida. The ultrasound exam demonstrated a 29 weeks fetus with an omphalocele, infraumbilical and supragenital irregular hyperechogenic mass that reminded of bladder exstrophy, wide lumbar myelomeningocele, left prominent and fixed knee, bilateral clubfeet and genital ambiguity. The fetus was suspected of having the OEIS complex. The diastolic flow was reduced in the umbilical artery. A female fetus was delivered after spontaneous premature labor. The findings were confirmed after delivery (see fig. below). Note that the neural tube defect is a skin-covered defect in this case.

Discussion

The fetal OEIS complex is a defect that affects the midline of the lower inferior hemibody. It occurs with an incidence of 0.025-0.04:10.000 births. Although its etiology is unknown several associations have been suggested: teratogenic exposure like dixilamin succinate, genetic factor (i.e.: 47XXX), sporadic familiar occurrence and possible multifactorial vascular embryonic disruption phenomena.

Embryology

Embryological it results from an arrest in the development of the urorectal septum in the 5-6 weeks embryo with inhibition of the later differentiation of the cloaca (1). Theatrically the fault occurs at the level of the initial mesoderm that would later contribute to the formation of the infraumbilical mesenchyma, cloacal partition and caudal vertebrae. This result in:

1. default of the cloacal partition with common cloacal persistence and imperforate anus,
2. rupture of the cloacal membrane with cloacal exstrophy,
3. lack of fusion of the genital tubercles and the pubic ramus of the pelvis bones often associated with an omphalocele
4. incomplete development of the lumbosacral vertebras, spina bifida, lipomyelomeningocele or dilated central canal of the spine cord (hydromyelia).

The illustration demonstrates the sagital and axial view of an embryo with normal (right side) and abnormal development. Note the absence of formation of the anterior abdominal wall with eversion of the back wall of the cloaca. The bladder is in blue the hindgut is green.

Associated anomalies include:

• two or more cecal appendix,
• cryptorchidia,
• penile agenesis or with epispadias,
• bifid uterus,
• vaginal duplication and
• bifid clitoris.

Most of the cases have a unique umbilical artery and also there are frequent lower extremities anomalies.

Diagnosis

The prenatal diagnosis is possible by the identification of:

• a midline infraumbilical defect or a cystic structure (if there is cloacal membrane persistence) or
• a protuberant irregular mass in the inferior abdominal wall,
• absence bladder in serial examinations,
• lumbo-sacral myelomeningocele,
• club feet,
• wide pubic arch,
• single umbilical artery,
• genital anomalies,
• anal atresia, and
• omphalocele or hepato-omphalocele although it presence is variable.
• the alpha-fetoprotein is elevated.

The OEIS complex was considerate fatal until 1970. The prenatal diagnosis, the improvement of surgical techniques, tissue manipulation and new antibiotics have diminished the mortality and have improved the prognostic of theses little patients. Nevertheless, these children will not have a “normal” life considering the problems of the urinary and fecal incontinence plus the incomplete genital development. The quality of life will depend on the severity of the anomalies, and the success of the corrective surgery procedures^4-15.

Summary

The fetal OEIS complex embraces a variable combination of genitourinary, intestinal and vertebral abnormalities that have a common and localized embryonic origin, it is a defect extremely rare but its comprehension illustrates the pathogenesis of the congenital defects in general, we describe a typical case of cloacal extrophy.

References

OEIS in OMIM

1- Chervenak F : Ultrasound in Obstetrics and Gynecology, Volume 2, Boston, Little Brown and Company, 1993.

2- Smith, D: Atlas de Malformaciones Somáticas en el Niño. Barcelona, Editorial Pediátrica, 1978.

3- Sosa Olavarría A.: Ultrasonografía y Clínica Embriofetal. Valencia, Editorial Tatum, 1994.

4- Austin PF.The prenatal diagnosis of cloacal exstrophy. J Urol 160:1179-81,1998.

5- Girz BA. First-trimester prenatal sonographic findings associated with OEIS (omphalocele-exstrophy-imperforate anus-spinal defects) complex : a case and review of the literature. Am J Perinatol  15 :15, 1998.

6- Hendren WH. Cloaca, the most severe degree of imperforate anus : expience with 195 cases. Ann Surg 228 :331-46, 1998

7- Wakim A. The pelvis of fetuses in the exstrophy complex. J Pediatr Orthop May-Jun 17(3) : 402, 1997.

8- Beaudoin S. Anatomical basis of a common embryological origin for epispadias and bladder or cloacal exstrophies. Surg Radiol Anat 19:11, 1997

9- Weaver KB. Vertebral column and spinal cord malformation in children with exstrophy of the cloaca, with emphasis on their functional correlates. Teratology Apr 55(4):241-8, 1997.

10- Bruch S. Challenging the embryogenesis of cloacal exstrophy. J Pediatr Surg 31:768, 1996.

11- Pinette MG. Prenatal diagnosis of fetal bladder and cloacal exstrophy by ultrasound. A report of three cases. J Reprod Med Feb 41:132, 1996

12- Meizner I. Cloacal exstrophy sequence : an exceptional ultrasound diagnosis. Obstet Gynecol 86(3):446, 1995.

13- Lin H. Exstrophy of the cloaca in a 47,XXX child : review of genitourinary malformations in triple-X patients. Am J Genet 45(6) :761,1993

14- Smith N. The OEIS complex (omphalocele-exstrophy-imperforate anus-spinal defects) : recurrence in sibs.  J Med Genet 29 :730, 1992

15- Kutzner D. OEIS complex (cloacal exstrophy) : prenatal diagnosis in the second trimester. Prenat Diagn 8 :247 , 1988