Number of Credits: 4 CME Credits
After completing this course, the participant should be able:
Tu T.T. Le, MD,
Philippe Jeanty, MD, PhD
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Physicians, sonographers and others who perform and/or interpret OB ultrasound.
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Estimated Time for Completion: Approximately 4 hours
Date of Release: November 23, 2012
Date of Most Recent Review: June 25, 2018
Expiration Date: June 24, 2021
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1.1. Prevalence: more than 100 neonatal cases have been reported.
1.2. Pathology: These are benign, functional cysts which result from enlargement of otherwise normal follicles known to be present during the third trimester and early neonatal period.
1.3. Associated anomalies:Congenital pyloric stenosis, hydrocephalus, agenesis of the corpus callosum, and fetal hypothyroidism have been reported.
1.4. Ultrasound features:
1.5. Differential diagnosis: sacrococcygeal teratoma type IV, lymphangioma, peritoneal cyst, pelvis kidney, anterior sacral meningocele.
Other rare anomalies: Hydrometrocolpos, anorectal atresia, persistent cloaca, and urachal cyst, however, these are not likely to be isolated findings.
1.6. Prognosis: Excellent if an isolated, unilateral and unilocular ovarian cyst is seen, since most are benign and some could regress near term or in the early neonatal period.
1.7. Management: Standard obstetrical care. Follow-up scanning is necessary.
1.8. Case report 1:
Ultrasound found a predominantly cystic structure (66x68 mm) within the fetal pelvis since 30 weeks. The neonate was delivered at term via Cesarean section (3360g) with distended abdomen and signs of intestinal occlusion and torsion of the ovarian cyst.
Images 1-4: Prenatal images of the fetal abdomen with cystic structure with the hyperechoic content represented ovarian cyst with intracystic hemorrhage
The surgery was done on day 70, the brown color cystic mass was confirmed to be a necrotic ovary. The tube was twisted 7 times and also appeared compromised.
2.1. Definition The most common congenital abnormality of the small intestine which is caused by an incomplete obliteration of the vitelline duct
2.2. Prevalence: 2% of the population. No sex and race differences. However, it is rare in prenatal diagnosis. In literature, less than 15 cases have been reported prenatally.
2.3. Associated findings Frequently isolated
2.4. Sonographic findings: A right-sided pelvic and anechoic or heterogenic mass, a fluid containing structure. In the early pregnancy, the mass could be anechoic because of fluid content. In later pregnancy, the Merkel diverticulum may contain intestinal debris and becoming hypoechoic which is mostly invisible on ultrasound at term because of the isoechoic mass similar to the intestinal loops. 2,Error! Bookmark not defined.
2.5. Differential diagnosis: other intra-abdominal cystic masses in the early pregnancy such as intestinal duplication, mesenteric cyst, choledochal cyst and urachal abnormality.
2.6. Management Follow-up prenatal ultrasounds. Surgical intervention after birth if there is complication..
2.7. Case report: A right-sided pelvic mass with thick walls (21 x 30 x51 mm) was identified at 12, 18, 25 and 28 weeks. It appeared to have peristalsis.
The postnatal x-rays suggested a giant Meckel’s diverticulum and this was confirmed at surgery
3.1. Definition: A kidney located outside the renal fossa and within the pelvis.
3.1. Prevalence: 8.3-11:10,000, 1:1 male-to-female ratio and may be bilateral in 10% of cases.
Abnormal positions are described as pelvic, iliac, abdominal, thoracic, and crossed; a few cases of ectopic kidneys have been reported antenatally .
3.3. Etiology: Failed migration of the ureteral bud and developing metanephric blastema to the renal fossa
3.4. Associated anomalies
Adrenal anomalies (rare)
3.5. Prenatal diagnosis:
The visualization of an empty renal fossa as well as an ectopic kidney can be diagnosed from the second trimester on Error! Bookmark not defined.. In case of multicystic kidney or hydronephrosis of the pelvic kidney, the appearance is of a cystic mass in the lower abdomen, therefore, pelvic kidney could be a differential diagnosis of other pelvic cystic masses.
3.6. Differential diagnosis:
duplicate collecting systems, ovarian cysts, mesenteric cysts, or sacrococcygeal teratoma.
3.7. Prognosis: Good in absence of other serious anomalies. However, hydronephrotic complications and calculi are more common with renal ectopia.
3.8. Recurrence risk
Unknown, probably small
A thorough anatomic survey should be undertaken to look for coexisting anomalies, especially of the fetal urinary system
3.10. Case report:
At 25 week, the kidneys were not seen within the renal fossa. A mass seen between the bladder and the sacrum seemed to be a pelvic kidney (Image 1, 2). The amniotic fluid volume was normal. Subsequent sonograms at 29 and 33 weeks confirmed this finding. The patient underwent a normal spontaneous delivery at term without complication.
Ureterocele is the herniation of the distal ureter, lying between the mucosa and the bladder muscle, ballooning inside the bladder. The abnormality leads to urinary retention and recurrent urinary tract infection, which can cause irreversible damage to the kidney . Four types of ureteroceles are described:
Ureteroceles are highly specific markers for the diagnosis of duplex renal system
1-2:10,000 in the general population and 1:500 newborn. Approximately 10% are bilateral, 60-80% are ectopic, and 80% are associated with an upper pole ureter of a duplex kidney. Ureteral duplication, ectopia, and ureteroceles are all more common in females and Caucasians.
4.3. Recurrence risk:Not known to be increased, but it has been reported in mono-and dizygotic twins, among brothers and in a mother and daughter.
4.4. Differential diagnosis:
4.5. Associated anomalies:Duplicated contralateral upper tract in 30-40% of cases, crossed-fused ectopia, dysplastic kidneys, abnormal testes and cardiac abnormalities
Aneuploidies: 49, XXXXY karyotype
4.6. Sonographic findings:Ureteroceles appear as thin-walled cyst-like structures within the bladder
Damage from obstruction is a progressive process, which may develop into bilateral renal dysfunction. As such it is important to perform serial ultrasonographic evaluations of fetal obstructive uropathies
4.7. Prognosis: The ureterocele alone has good prognosis.
4.8. Management: Follow-up ultrasound scanning is required during pregnancy.
The ureterocele rarely requires additional surgery. Surgical intervention after birth depends on the associated findings, the severity of obstruction and the renal function.
4.9. Case report:
A routine examination at 15 weeks of gestation demonstrated bilateral pyelectasis (left = 7mm, right = 5mm). Control examination at 24 weeks revealed a duplicated collecting system with ureterocele in the bladder.
5.1. Definition: Urinoma is a fluid mass formed by extravasated urine encapsulated in the perirenal fascia. It is also known as pseudohydronephrosis or pararenal pseudocyst
5.2. Incidence: Rare. There were more than 27 case reports of fetal urinoma in a literature review
Fetal urinoma is an uncommon finding in prenatal investigations29. Most previous reports have referred to the presence of an obstructive uropathy and thus to very high pressures in the upper urinary tract during fetal life causing urinomas. The cause of urinoma is not often visible on prenatal investigations. Urinoma secondary to an obstructive uropathy are easy to correlate, since the renal rupture represents a protective mechanism to reduce the high pressure in the urinary tract and to preserve the integrity of the kidney , . Fetal urinoma was also known to occur secondary to urinary tract obstruction such as that found in ectopic ureterocele or partial ureteral atresia or after a traumatic amniocentesis
5.4. Associated findings:It can be associated with urinary obstruction such as posterior urethral valves or ureteropelvic junction obstruction.
5.5. Sonographic findings:A fluid-filled cyst surrounding the ruptured structure of collecting system with or without presence of an obstructive uropathy, mostly of the posterior urethral valves, uretro-pelvic junction obstruction, primary obstructive megaureter, anterior urethral diverticulum and rarely vesico-uretral reflux
5.6. Diagnosis and differential diagnosis: The diagnosis should be considered when a retroperitoneal cystic mass is associated with signs of upper or lower urinary tract obstruction 33. Urinomas usually lead to anterior displacement of the ipsilateral kidney and this should be considered whenever a retroperitoneal cystic mass is detected. Urinoma must first be differentiated from hydronephrosis. Other causes of a retroperitoneal cystic mass, such as lymphangioma, hemorrhagic neuroblastoma, mesenteric cyst, enteric duplication and other cystic renal diseases, such as multicystic kidney, polycystic kidney disease and Wilms tumor also have to be excluded.
5.7. Management: Intervention to reduce the size of the urinoma does not affect the outcome, nor does in-utero aspiration: the fluid simply reaccumulate
5.8. Prognosis: The probability of a non-functional dysplastic ipsilateral kidney is about 80% and the subsequent life-threatening risk is oligohydramnios or pulmonary hypoplasia in cases of bilateral urinomas or urinoma in a single kidney
5.9. Case report: Posterior urethral valve with bladder rupture and urinoma at 35 weeks.
The ultrasound examination showed urinary ascites with ruptured urinary bladder. The cause of the rupture was posterior urethral valve causing lower urinary tract obstruction. Bladder wall was thickened due to previous extreme distention. There was a visible defect of the urinary bladder wall through which the urine leaked out into abdomen. One of the kidneys showed mild hydronephrosis. The opposite kidney decompressed itself by rupture of the collecting system. The perinephric urinoma formed by urine draining into the retroperitoneal space. The neonate died shortly after delivery.
Meningocele is a form of closed neural tube defect in which no cerebral tissue, spinal cord or spinal nerves is herniated, only the meninges protrudes out of the calvarium or the spinal column.
Anterior sacral meningocele is herniation of the meningeal sac into the retroperitoneal pelvic region through a congenital defect in the sacrum
6.2. Incidence:The incidence of myelomeningocele varies according to geographical origin. From 3-6:10,000 live births in Japan and Scandinavia 30:10.0000 and 32-41:10.000 live births in England and Wales. Sacral meningoceles represent approximately 20% of all meningocele
The meningocele can be part of skull and spinal defect as well. The spinal meningocele are mostly located posterior to the spinal cord (80% of spinal meningocele case),42 including thoracic spine (70%), thoracolumbar junction(12%), lumbosacral (13%) and cervical (3%) spine. Rarely, they can be seen as anterior and lateral meningocele.
More than 200 case of anterior sacral meningocele have been reported postnatally, and to our knowledge, approximately 16 cases diagnosed prenatally predominantly to females.49 One newly case of prenatal diagnosis has been reported in literature 51 and two others on TheFetus.net.
Familial inheritance of anterior sacral meningocele has been reported.
6.5. Associated findings:
90% of patients have associated occult spinal lesions such as tight filum terminale, split cord malformation, and epidermoids
The Currarino syndrome: anterior sacral meningocele was reported to be associated with other malformations in the so-called Currarino syndrome or triade. It includes anorectal malformations, sacral bony defect, and presacral mass. The etiology is unknown, but recent report of an association with caudal split cord, suggested an embryogenetic mechanism originating in a failure of dorso- ventral separation of the caudal eminence from the hindgut endoderm during late gastrulation
Marfan syndrome - anterior sacral meningocele was reported to be associated in 21% of the cases compared to around 200 cases among the general population . The etiology is presumed to be connected to the disorder of collagen biosynthesis and structure at the dural level. Only 12 cases were reported on Pubmed until 2007
6.6. Sonographic findings:
Anechoic, well-defined mass separated from the other organ, located in the midline posterior abdomen and protruding from the sacral spine. If the cyst is big, it is difficult to find the spinal canal through the spine and distinguish from the other structure because its displacement.
Good if there is no associated anomalies. Some cases are only detected in adolescent with anterior sacral meningoceles slowly enlarging over time, or are have been found out in later life incidentally or for protean neurologic, urological or gastrointestinal complaints
Surgery is necessary after birth, there is no spontaneous regression.
6.9. Differential diagnosis:
6.10. Case report:
This second trimester fetus was referred for a cystic pelvic mass behind the bladder.
We subsequently decided to drain the cystic mass.
The sacrococcygeal teratoma is defined as a neoplasm composed of tissues from all three germ layers. Commonest sites are the sacrococyx, although they may occur near the midline from the brain to the coccyx.
7.2. Prevalence: It is the most common tumors in newborns (1/35,000 to 1/40,000 live births), and it is more common in females than males (4:1).
7.4. Sonographic findings:
Most of these tumors are solid or mixed solid and cystic. Polyhydramnios is a common sign and non-immune hydrops has also been seen in association. The differential diagnosis includes lumbosacral myelomeningocele, hemangioma, neurofibroma, lipoma. Only 10% of all the sacrococcygeal teratomas are entirely intraabdominal (Type IV). Of this group, only 15% are entirely cystic.
7.5. Differential diagnosis:
The frequency of malignancy is 10% when the diagnosis is done less than 2 months after birth, but for diagnosis after 2 months the frequency of malignancy rises to more than 50%. Benign neoplasm can transform into malignancy. So, surgical removal is advisable.
7.7. Management: Surgical intervention after birth.
7.8. Case report :
In this case, the problem was not to identify the finding: everyone recognized that there was an extra cystic structure in the pelvis. Actually, during the original scan this was not quite so obvious since the pelvic bones were partially shadowing the bladder.
The difficulty of identifying the presence of a problem can be appreciated in the 8 first images. These were done after we had suspected the diagnosis. These images were obtained to maximize the visualization of the extra cyst and the bladder. When the extra cyst was suspected we obtained parasagittal views through the pelvis (the last 3 images).
The last 2 images demonstrated a normal spacing of the lumbar spine and the absence of spina bifida.
The normal cystic structure is the bladder that is the more anterior and superior cyst in the images. Note on the second image the umbilical arteries coursing around the bladder.
Importantly, there were no images of: abnormal cerebellum and posterior fossa, distended loops of bowel, obstructed kidneys.
Therefore the findings were that of several cysts (2 were identified but several months later at surgery there were 4) that are posterior and inferior to the bladder.
The pathology confirmed that the tumor was a predominantly cystic mature cystic teratoma containing mature epithelial mesenchymal and neural elements. The post surgical course was uneventful.
Incomplete or intermittent obstruction of the urethra due to posterior urethral valves.
Posterior urethral valve which is the most common cause of bladder outlet obstruction occurs sporadically and in 3:10,000 male fetuses.
The incidence of posterior urethral valves has been reported to be between 0.25–0.5:10,000 births. It accounts for 10% of all urological anomalies detected by prenatal ultrasound. The overall mortality is 25–50%. Renal insufficiency develops in up to 45% of survivors.
Posterior urethral valves are thought to be embryologically derived from Mullerian duct remnants or remnants of the cloacal membrane dating back to between the 7th and 11th week of gestation. The urethral membrane acts as valve, resulting in bladder outlet obstruction.
8.4. Associated findings:
Fetuses with obstructive uropathy can also have other associated anomalies, like chromosomal abnormalities (especially trisomies 13, 18 and 21), and some deformations related to the oligohydramnios.
8.5. Sonographic findings:
There is usually incomplete or intermittent obstruction of the urethra which is associated with an enlarged and bladder hypertrophy, hydroureters and hydronephrosis. Depending on the severity of urethral obstruction, the renal function could be affected and result in renal hypoplasia and dysplasia, oligohydramnios and pulmonary hypoplasia. The appearances on ultrasound are variable due to gestational age and the various stages of obstruction. The typical finding is the "key-hole" sign due to the dilated proximal urethra extending from the bladder toward the fetal perineum. In some case, there is urinoma associated because of bladder rupture or transudation of urine into the peritoneal cavity.
Evaluation of fetal renal function based on ultrasound findings and analysis of fetal urine. Intrauterine surgery intervention to improve renal and pulmonary function is still controversial.
Poor if there is degraded fetal renal malfunction and other associated findings.
8.8. Case report:
Case 1: Posterior urethral valves, 15 weeks. The examination revealed a massively distended bladder from posterior urethral valves. The pregnancy was terminated at 16 weeks of gestation. We still saw a little amniotic fluid which is absolutely not present in urethral agenesis.
Amniocentesis was performed with a normal result, karyotype 46 XY.
Posterior urethral valves, 22 weeks
Ultrasound revealed oligohydramnios, a male fetus with bladder distention without ascites. The right kidney had mild dilatation and the left kidney had moderate dilatation. The patient opted for pregnancy termination at 23 weeks. Catheterization of the urethra was not possible and the diagnosis was confirmed.
Right and left kidney, a "keyhole" deformity of the posterior urethra
The following images show a case of the posterior urethral valves diagnosed at 13 weeks of a pregnancy. (Note that the amniotic fluid is still abundant)
The difference between urethral atresia and agenesis is not clear. Whether the condition is an absence, a partial absence or an occlusion of the urethra is often unclear.
The antenatal detection of urethral agenesis has rarely been documented. It occurred in male and female fetuses and in fetuses of diabetic mothers.
9.3. Ultrasound findings:
Megacystis, hydroureter, hydronephrosis, renal dysplasia and anhydramnios sequence such as pulmonary hypoplasia, Potter face and limb deformities.
9.4. Implications for targeted examinations:
Bladder outlet obstruction findings such as megacystis, hydroureter, hydronephrosis, echogenic kidney, "keyhole sign", ambiguous or absence of fetal external genitalia and oligo-anhydramnios and its sequences
9.5. Differential diagnosis:
The differential diagnosis of oligohydramnios and distended bladder could include other obstructive uropathy such as posterior urethral valves, detrusor hypertrophy, urethral meatus agenesis or congenital urethral membranes . Posterior urethral valves are much more common than urethral atresia and occur in the prostatic urethra and can lead to a similar sequelae and anomalies. However, in posterior urethral valves, the fetal gender, male, is a significant factor in the differential diagnosis.
9.6. Associated anomalies:
Urethral atresia was found most commonly in association with other genitourinary anomalies . Chromosomal abnormalities have been described but relation with urethral atresia is unclear.
The prognosis is mostly fatal unless there is an associated urachal fistula or rectovesical fistula that allows the drainage of the bladder, or surgical intervention (shunt placement) can be performed before renal cystic dysplasia occurs.
9.8. Recurrence risk:
Not known to be increased. Although in one study there was in increased risk of recurrence in patients with a urethral atresia.
Complete bladder outlet obstruction detected in the first or early second trimester without spontaneous drainage or intervention is a lethal condition. It was reported that a survival rate in the presence of poor serial urine electrolytes is 30%. Prenatal recognition of this entity at early stage might permit operative urinary diversion. There is a small number of reports of urethral atresia who underwent successful urinary decompression by intrauterine placement of a vesico-amniotic shunt at early stage.
9.10. Case report:
This second trimester was performed for routine assessment with unremarkable history. The findings were an enormous cystic collection that displaces and deforms the fetus, no amniotic fluid. This combination points to a major obstruction of the bladder outlet. Several conditions can cause that such as posterior urethral valve, urethral meatus agenesis but these usually present with some amniotic fluid. So a more severe condition like urethral agenesis was suspected and confirmed postnatally.
The absence of external genitalia was revealed after birth.
These images demonstrate anhydramnios and a large cystic multilocular abdominal mass at 21 week:
Anhydramnios is important sign, since other masses like lymphangiomas could look like the one in this case, but the anhydramnios is highly suggestive of an obstructive urinary process.
This mass is fairly typical for massively distended ureters. The wispy septation seen in the cystic mass represents the folding of the ureters. The diagnosis is then simply that of urethral agenesis. Compare to case 1 where the cystic mass represented the distended bladder. Here the bladder is barely seen, but the most visible sign is that of the bunched up ureters. After delivery of the fetus, the massively distended abdomen was seen and there was a concomitant anal atresia.
10.1. Prevalence: rare.
10.2. Definition: Absence of urethral meatus.
10.4. Associated anomalies:
The male urethra consists of the prostatic, membranous and spongy portion which expands into the glands and forms the meatus at its apex (navicular fossa). The epithelium of the prostatic, membranous and spongy urethra is derived from the endoderm of the urogenital sinus. However, the epithelium of the glandular portion of the spongy urethra develops by canalization of an ectodermal cord of cells–the glandular plate–that extends into the glands from its tip. Faulty connections or development of this plate probably account for meatus atresia.(67)
The urethra is composed of a spongious portion of endodermal origin and a portion of ectodermal origin: the glandular plate. The glandular plate canalizes to form the external urethral ostium. The normal connection between the two results in the normal urethra (top right) while the failure of connection results in meatal atresia (bottom right).
10.6. Differential diagnosis:
The differential diagnosis of oligohydramnios and a distended bladder could include other lower obstructive uropathies such as posterior urethral valves, detrusor hypertrophy, urethral agenesis or congenital urethral membranes. The megacystis-microcolon-intestinal hypoperistalsis syndrome consists of the association of a distended unobstructed bladder, a dilated small bowel and distal microcolon, secondary to degeneration of smooth muscle involving these organs (68).It is usually seen in association with normal or increased amniotic fluid and therefore can easily be differentiated.
Posterior urethral valves are much more common than urethral meatal atresia and occur in the prostatic urethra and can lead to a similar sequela of anomalies. However, since the obstruction is the proximal portion of the urethra, the urethral dilatation and megaphallus are absent (69).
Urethral dilatation or urethrotomy at birth has been used to create a functioning urethra. However, only the infants with minimal renal dysplasia do well.
Incompatible with life unless an alternate bladder outlet develops, such as a patent urachus or rectovesical fistula.
10.9. Case report:
22 weeks of gestation, ultrasound revealed anhydramnios, 2–vessel umbilical cord, dilated bladder, enlarged and cystic kidneys, myocardial echogenicity which is suggestive of endocardial fibroelastosis, pericardial effusion, and a left ventricular chamber that was larger than the right one.
The autopsy revealed absence of right kidney, presence of large left multicystic dysplastic kidney ureter and testis with urethral meatus atresia. The bladder was distended. The scrotal sac was absent and the urethra ended in a blind pouch in a markedly distended penis (Image 3).
The only other anomalies were a 2-vessel cord and undescended but normal left testis. The rest of the examination was normal (including the abdominal musculature, cardiac and skeletal systems). The chromosome analysis was normal (46XY).
Hydrocolpos is the fluid accumulation in the vagina.
During fetal life, hydrocolpos involves the dilatation of the vagina due to obstruction of the genital tract, leading to accumulation of secretions. If there is also uterine distention, it is called hydrometrocolpos.
Hydrocolpos and hydrometrocolpos account for 15% of abdominal masses in female neonates, surpassed in frequency by hydronephrosis. The estimated global prevalence is 2:10,000. The estimated incidence of hydrocolpos is 0.6:10,000 .
The obstruction can be due to a transverse vaginal septum, or vaginal or cervical atresia. Literature reports an occasional association with other congenital anomalies; simple imperforate hymen is almost always an isolated finding. Nevertheless, it is essential to recognize hydrometrocolpos and hydrocolpos.
The incomplete absence of the fusion and canalization of the mullerian ducts, often associated with the defects of the urogenital system
11.5. Associated anomalies
Vaginal septum, vesical-vaginal fistulas, vesical-uterine fistulas, urethral-vaginal fistulas or cloacal anomalies and urinary tract obstruction.
Congenital imperforate hymen is an external urogenital anomaly . An imperforate hymen is usually detected in the neonatal period when the infant presents with physical signs of lower abdominal swelling and a characteristic bulging membrane at the introitus70. It can also manifest at menarche as either cyclic abdominal pain with pelvic distension or urinary obstruction
11.6. Ultrasound findings:
This anomaly could be diagnosed early in the second trimester. Hydrometrocolpos is possibly associated with urinary tract obstruction, hydronephrosis, oligohydramnios. Ultrasound findings include: an ovale-shape hypoechogenic or anechoic well-defined mass, sometimes it could observed as a cystic mass elongated to the vagina (distended vagina) on the female fetus.
11.7. Differential diagnosis:
Vaginal atresia may be of congenital origin or may be acquired. In the majority of cases, the first clinical symptoms of defects caused by vaginal atresia can be recognized during menarche. The stretch over the blockage enlarges significantly and causes tense lower abdominal cramp-like pain with occasional disorders of urination and/or defecation. Although our ultrasound results led us to suspect that the most likely cause was the narrowing of the urethral valve, this was excluded almost immediately after birth with participation of pediatric specialists. So our diagnosis was confirmed after the delivery only.
Intrauterine intervention (draining or shunting) can be necessary if the dilated uterus and vagina are causing a significant enlargement of the fetal kidneys. Thus, early postnatal therapy (surgical procedure) should be done.
The complication of hydrocolpos is to worsen obstructive uropathy because of the direct compression by the massive hydrocolpos on both lower ureters, worsening oligohydramnios. The prognosis of a simple hydrocolpos is excellent but familial recurrence has been observed.
By surgical incision of the bulging membrane, the trapped utero-vaginal secretions are drained. However, if vaginal obstruction is caused by a mid transverse septum or vaginal atresia, the prognosis mostly depends on the presence and severity of associated disorders. When there is hydrometrocolpos, retrograde passage of the secretions through the Fallopian tube into the peritoneal cavity leads to an aseptic peritonitis and secondary ascites especially during the third trimester. The postnatal course might be complicated by cardio-respiratory distress secondary to marked abdominal distension.
11.10. Case report:
Images show Transverse view at 28 weeks showing the presumably imperforate hymen and hydrocolpos
Images show notice the distended vagina.
Images show 3D view at 28 weeks
Images show MRI at 32 weeks showing a retrovesical non-septated cystic mass
Images show Neonatal view of the vulva a few minutes after delivery
Congenital megaurethra is diffuse dilatation of the anterior urethra due to nondevelopment of erectile tissue of the penis. It is characterized by dilatation of the penile urethra without distal obstruction (such as phimosis).
12.2. Prevalence: rare, some described in literature was isolated and had a normal karyotype..
12.3. Sonographic findings:
Most cases of congenital megaurethra revealed between 16 and 24 weeks and present with distended bladder and megaurethra or a penis with a cystic urethra. The consequences for the upper renal tracts can be different: Megacystitis without duplicated collecting system; Pyelectasis with or without ureteral dilatation. Oligohydramnios is possible.
12.4. Differential diagnosis:
Megacystitis; Posterior urethral valves; Anterior urethral valves; Meatal agenesis; Prune-Belly syndrome.
12.5. Associated anomalies:
Approximately 70% of cases of congenital megaurethra present with structural and functional urinary defects. Congenital megaurethra may be associated with other systemic anomalies such as cardiac anomalies or intestinal malrotation, various in type and severity. Congenital megaurethra can lead to urinary retention, incontinence, enuresis, megacystitis, and, exceptionally, spontaneous rupture of bladder.
12.6. Associated syndromes:
Very poor perinatal outcome. If urethral obstruction occurs, congenital megaurethra is lethal without patent urachus or rectovesical fistula.
Congenital megaurethra can be diagnosed prenatally, the earlier the better, so that interruption of pregnancy, if desired, is possible before viability.
12.9. Case report:
This case initially thought to be megacystitis with posterior urethral valves.
Amniocentesis was 46, XY. Autopsy showed bilateral dysplastic kidneys and a large bladder were seen. The scrotal sac was present, the penis was distended, and the distended urethra ended in a blind pouch.
In our case at 18 weeks, fetal keratinization had not yet occurred, so amniotic fluid was normal.
Images show Dilated urinary bladder and proximal urethra.
Communication between the dome of the bladder and the umbilicus.
The umbilical cord may be dilated distal to the cystic mass from absorption of fetal urine by Wharton’s jelly.
Congenital patent urachus is a rare anomaly with an estimated incidence of 0.25:10,000 deliveries . Males are affected twice as commonly as females.
Embryologically, the urachus is a derivative of the allantois. The allantois appears on day 16 post-conception as an outpouching of the caudal wall of the yolk sac. It functions as an embryonic bladder, in early blood formation and in formation of the definitive bladder. Normally, the extraembryonic part of the allantois degenerates during the second month of gestation. Occasionally, trace remnants of the allantois remain in the proximal umbilicus and may be seen between the umbilical arteries on pathologic examination of fetuses at this gestational age. The intraembryonic portion forms a connection from the umbilicus to the apex of the bladder. As the bladder enlarges, the allantois involutes to form the urachus. The urachus has little function after the second month of gestation. After birth it becomes a fibrous cord which remains in the adult as the median umbilical ligament. Failure of the urachal lumen to close can result in a variety of anomalies including complete luminal patency (patent urachus), distal urachal patency (urachal sinus), proximal patency (urachal diverticulum), and urachal cysts.
13.4. Pathogenesis:Partial or absence of obliteration of the allantois.
13.5. Associated anomalies:Although usually not associated with other anomalies, one series has reported a 46% incidence of anomalies including: omphalocele, omphalomesenteric remnant, meningomye-locele, unilateral kidney, hydronephrosis and vaginal atresia.
13.6. Differential diagnosis
The differential diagnosis of patent urachus includes anterior abdominal wall defects, bladder exstrophy, vascular lesions of umbilical cord (hemangioma, varix, true knot) or allantoic or omphalomesenteric cysts. Documentation of a normal umbilical cord insertion into the fetal abdomen along with integrity of the anterior abdominal wall help exclude omphalocele and gastroschisis. Lack of Doppler signals in the cyst excludes vascular lesions of the cord. The prenatal diagnosis of bladder exstrophy has been described3, and this lesion can be ruled out by the anechoic nature of the cyst and documentation of a fetal bladder. The presence of a direct communication between the bladder and the umbilical cord cyst will confirm the diagnosis of patent urachus. The umbilical cord may be dilated distal to the cystic mass and this may be related to absorption of fetal urine by Wharton’s jelly.
Excellent when associated anomalies are absent.
13.8. Recurrence risk:
13.9. Management: Surgical excision at birth.
13.10. Case report:
A 22 year old G3P1011 with an uncomplicated prenatal course was referred to the antepartum diagnostic unit after a routine dating ultrasound revealed a large cystic mass located at the anterior abdominal wall of the fetus. Her medical and obstetrical histories were unremarkable. Fetal biometry was consistent with a 33 week gestation which was compatible with menstrual dates. The umbilical cord was enlarged at the fetal insertion site. There was an anechoic cystic mass measuring 2.3 x 2.0 cm located within the umbilical cord. The umbilical arteries and vein were noted to be separate from the cystic mass (Image 1).
Both the umbilical cord and the umbilical vein were dilated distal to the cyst. The umbilical cord insertion into the fetal abdomen appeared normal. The fetal bladder was enlarged and distorted. In an oblique longitudinal scanning plane, a direct communication between the bladder and the umbilical cord cyst was documented. The umbilical artery and vein could clearly be seen entering the fetus adjacent to the fistula tract (Image 2).
Pulsed wave Doppler of the umbilical arteries proximal and distal to the cyst demonstrated normal indices for gestational age. Also, Doppler analysis of the cyst failed to document flow. The fetus was male, and the fetal bladder was seen to fill and empty. No other fetal anomalies were seen, and the amniotic fluid volume was normal. Diagnosis suggested a congenital patent urachus. The patient was counseled regarding these findings and offered genetic studies, which she declined.
Serial ultrasound exams documented normal fetal growth. The size of the umbilical cord cyst remained unchanged throughout the remainder of the pregnancy. Serial umbilical artery Doppler indices proximal and distal to the cyst showed no vascular occlusion and remained normal for gestational age. The fetal biophysical profile and non-stress test also remained normal. A healthy male infant weighed 3690g with Apgars of 9 and 9 at 1 and 5 minutes, respectively, was delivered vaginally without complications.
Initial neonatal examination revealed a 3x2 cm cyst at the inferior margin of the umbilicus which was observed to drain urine. Voiding was aslo documented from the penile urethra. Renal ultrasound and a voiding cystourethrogram were both normal. The baby initially had hyperbilirubinemia secondary to ABO incompatibility which resolved with phototherapy. On the eighth day of life, the urachus was surgically ligated. The surgical pathology revealed transitional epithelium consistent with urachus. The baby was discharged in good condition, and follow-up exams revealed no complications.
14.1. Synonyms: Neonatal hollow visceral myopathy. Berdon syndrome.
14.2. Definition:Megacystis-microcolon-intestinal hypoperistalsis syndrome consists of the association of a distended unobstructed bladder, dilated small bowel, microcolon, and decreased or absent peristalsis with ganglion cells present..
14.3. Prevalence: Male-to-female ratio is 1 to 4. Megacystis-microcolon-intestinal hypoperistalsis syndrome is more common in females , perhaps due to underdiagnosis in males who are labeled instead as "Prune-Belly".
14.4. Etiology: Most cases are sporadic. An autosomal recessive inheritance has been supported by reports of affected siblings.
14.5. Sonographic findings:Megacystis-microcolon-intestinal hypoperistalsis syndrome should be considered in the presence of an abnormally distended bladder with a normal or increased amount of amniotic fluid.
14.6. Diagnosis: In all cases, the enlarged bladder and absence of oligohydramnios typical of this syndrome. Polyhydramnios is present in approximately 25% of the cases.
It should be noted though, that the dilatation of the bladder may not be visible in some cases at the 18-20 weeks exam, and that the earliest sign maybe mild hydronephrosis.
14.7. Differential diagnosis:The main differential diagnosis is obstructive uropathy. In a female fetus, a low urinary tract obstruction can be due to urethral agenesis, variants of caudal regression syndrome, or to the rare detrusor hypertrophy . All of these cases are associated with severe oligohydramnios. Megacystis-microcolon-intestinal hypoperistalsis syndrome must be distinguished from isolated "Prune-Belly" caused by urethral obstruction. Prune-Belly occurs predominantly in males, is commonly due to posterior urethral valves and has a low recurrence risk.
14.8. Associated anomalies: Omphaloceles, cardiac malformations and multiple rhabdomyoma; Mild webbing of the neck and intra-abdominal testis have also been associated with this syndrome
Megacystis-microcolon-intestinal hypoperistalsis syndrome is lethal in most cases. An intrauterine death has been described . Intestinal dysfunction is the cause of death despite hyperalimentation. Septicemia has been reported as the cause of death in several infants. One child has been maintained on total parenteral nutrition for 7 years. But these children on long term parenteral nutrition may develop various deficiencies. There are no reported cases of long term survivors.
14.10. Recurrence risk: 25%.
Although most cases are sporadic, an autosomal recessive inheritance is likely since at least six pair of affected siblings and four cases where the parents were consanguineous have been reported
14.11. Management: Treatment has been shown to be ineffective. Obstetrical management should include a careful search for associated anomalies. Considering the poor prognosis, pregnancy termination may be offered to the patient.
14.12. Case report: A routine ultrasound examination at 21 weeks revealed a single female fetus with a markedly distended bladder and normal to increased amniotic fluid volume.
Images show several views that demonstrate the enlarged bladder reaching up to the chest
The second exam at 23 weeks again demonstrated increased amniotic fluid. The bladder was much more distended and extended into the left upper quadrant of the fetus filling the pelvis and part of the abdomen. Due to the poor prognosis, the patient decided to terminate the pregnancy. The autopsy revealed a markedly distended bladder filling the abdominal cavity with no urethral stricture or gross evidence of mechanical outlet obstruction. Mild hydronephrosis was noted bilaterally without hydroureter.
The uterus and ovaries were unremarkable. The small bowel was shortened length (primarily jejunum and ileum) with mildly decreased caliber of distal ileum without proximal dilatation (Image 4, 5). The large bowel was normal.
These findings confirmed the diagnosis of megacystis-microcolon hyopoperistalsis syndrome.
15.1. Synonyms: Cloacogenic bladder; ano-rectal malformation; extensive cloacal malformation; sinus urogenitalis; urogenital sinus.
15.2. Incidence:0.3-0.5: 10,000 births, the majority in girls.
15.3. Etiology: Cloaca is a single canal into which the urinary, genital and intestinal tracts lead at about 5th - 6th week of gestational weeks. Persistent cloaca is a consequence of failure of the urogenital septum to divide rectum from urogenital sinus. It may be related to B-class Eph/ephrin signaling.
15.4. Sonographic findings: There is an increased suspicion of persistent cloaca, when cystic abdominal masses, gastrointestinal, and urological abnormalities are present together.
Some of the sonographic features of the ano-rectal malformation (fluid dilated colon and pseudo-phallus) may disappear in the mid-gestation and though the "optimal time" to diagnose these anomalies is during the first and early second trimesters.
15.5. Differential Diagnosis:
15.6. Associated Anomalies:Uterine anomalies (bicornuate, cervical atresia), vaginal atresia or duplication; hydronephrosis, kidney agenesia, imperforate anus, polycystic kidneys, esophageal atresia and sacral hypoplasia.
15.7. Management and prognosis: Vaginal catheterization for hydrometrocolpos and surgical correction is use, with good results.
15.8. Case report:
Images 1, 2: 15 weeks; intraluminal enterolithiasis of the fetus with shadowing behind the lithiasis (labeled) and abnormal external genitalia of the fetus with incomplete fusion of the labio-scrotal folds (arrows) and pseudo-phallus (chromosomal female gender).
Image 3, 4: 15 weeks, abnormal kidney of the fetus-doubled renal pelvis and pyelectasis; dilated malrotated colon of the fetus, filled with urine in due to the persistent cloaca.
Of course this fetus has a little of ascites around the bladder (pink arrow). The two little "rabbit ears" on top of the bladder represents the 2 horns of a bicornuate uterus.
The fluid inside the images usually contains small echoes that represent uterus secretion (mother hormonal stimulation) or blood.
16.1. Definition: Imperforate anus is an anorectal malformation in which anus has no communication to the rectum.
The prevalence is approximately of 2:10,000 live births. No know sex predilection has been reported.
The familial inheritance was also suggested (OMIM #301800, 207500). However, to our knowledge, 5 cases of isolated imperforate anus in monozygotic twins has been reported.
16.3. Asssociated findings: Genitourinary abnormalities, vertebral, anorectal, tracheoesophageal, renal, and limb anomalies (VACTERL), as well as cardiovascular malformations.
Boys are likely to have enterourinary fistulas more than girl while girls have a high incidence of enterovaginal fistulas and cloacal anomalies.
16.4. Sonographic findings:
A dilated distal bowel or rectum appears as a fluid-filled structure in the lower abdomen distinguished from the bladder. There is no polyhydramnios unless associated upper tract problem.
Most of anorectal atresias are not diagnosed prenatally. Dilation of the colon was clearly seen in the first and third trimester but difficult to see in the second trimester.
16.5. Differential diagnosis: Hirschsprung’s disease, colonic atresia.
16.6. Management:Early surgical intervention is necessary after birth.
Prognosis depends on the severity of the imperforate anus, the position of the lesion and the presence of associated anomalies. However, the long-term functional outcome and quality of life either in low or high anorectal malformations are mostly not positive.
Renal anomalies (e.g., absence, agenesis, ectopia, horseshoe kidney) are more common and severe in children with a high imperforate anus.
6.11.1 Case report:
The fetus was delivered two days later and an imperforate anus was confirmed (a small cutaneous fistula was noted). Further, some degree of lumbar spine dysraphism was also noted.
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