Pathogenic implications of remnant vitelline structures in gastroschisis.

PURPOSE: The pathogenesis of gastroschisis is unknown. It may be helpful in understanding its pathogenesis to know the structural relationships among umbilical components including umbilical vessels, urachus, and vitelline structures, and thus, the authors investigated the remnants of vitelline structures in a series of cases of gastroschisis. METHODS: Medical records of 41 cases with gastroschisis treated in our institute from 1979 to 2009 were retrospectively reviewed. RESULTS: Paraumbilical bands, possible remnants of vitelline structures, were observed in 4 cases (9.8%). All 4 bands were attached to the skin edge of the abdominal defect without incorporation into the umbilical cord. The band ended at the mesentery in 3 cases and at the antimesenteric site of the ileum in the remaining case. Histologic findings showed fibrous tissues in all cases. One was possibly associated with the development of colonic atresia. Another was noticed after silo reduction when herniated bowels became strangulated by the band. The other 2 cases were uncomplicated. CONCLUSIONS: Our findings may support the recently proposed hypothesis that the developmental failure of the yolk sac and related vitelline structures to merge with or to be incorporated into the umbilical stalk might be associated with the pathogenesis of the abdominal wall defect in gastroschisis. Paraumbilical bands derived from vitelline structures may possibly cause intestinal ischemia prenatally or postnatally.

Structural and ontogenetic study of the urachus in human fetuses.

The objective of this work was to conduct an ontogenetic and structural study of the urachus. We studied 40 human fetuses (13-20 weeks post conception, WPC). The urachus was stained in Masson's trichrome, to quantify connective tissue and smooth muscle and to determine the urachal lumen area. Weigert's resorcin-fuchsin was used to observe elastic fibers, and picrosirius red and immunohistochemistry analysis were used to observe collagen. The images were captured with Olympus BX51 microscopy and an Olympus DP70 camera. The stereological analysis was done using the software Image Pro and Image J, to determine volumetric densities. For biochemical analysis, the collagen concentrations were expressed per milligram of dry tissue. Means were compared using the unpaired t test (p < 0.05). Quantitative analysis documented a statistically insignificant increase (p = 0.1475) in volumetric densities of smooth muscle in the urachus of males (23.02%), when compared with females (18.43%), and a statistically significant increase (p = 0.0439) in volumetric densities of connective tissue in the urachus of females, (67.64%) when compared with males (58.38%). Total collagen concentrations in the male (31,919-56.792 microg/mg, mean 45,656) and female fetuses (33,485-48,527 microg/mg, mean 42,308) did not differ significantly (p = 0.5912). At higher gestational ages, the urachal lumen area was smaller. In 13th WPC fetuses, the urachal lumen area was 16,301 microm(2) and in 17th WPC fetuses, the urachal lumen area was 1,676 microm(2). We determined that the urachal lumen was closed from the 17th WPC in all fetuses.

Urachal tumour: case report of a poorly understood carcinoma.

BACKGROUND: Urachal carcinoma is an uncommon neoplasm associated with poor prognosis. CASE PRESENTATION: A 45-year-old man was admitted with complaints of abdominal pain and pollakisuria. A soft mass was palpable under his navel. TC-scan revealed a 11 x 6 cm tumor, which was composed of a cystic lesion arising from the urachus and a solid mass component at the urinary bladder dome. The tumor was removed surgically. Histological examination detected poor-differentiated adenocarcinoma, which had invaded the urinary bladder. The patient has been followed up without recurrence for 6 months. CONCLUSION: The urachus is the embryological remnant of urogenital sinus and allantois. Involution usually happens before birth and urachus is present as a median umbilical ligament. The pathogenesis of urachal tumours is not fully understood. Surgery is the treatment of choice and role of adjuvant treatment is not clearly understood.

[Benign urachus abnormalities: embryology, diagnosis and treatments]. / Pathologies bénignes de l'ouraque chez l'adulte : origine embryologique, présentation clinique et traitements.

Urachus pathologies are very rare but require to be known by urologists. Lack of appropriate treatment exposes the patients to the risks of symptoms recurrence, infectious complications or adenocarcinomatous degeneration. A partial or total defect of obliteration of the urachus channel after the fifth month of gestation can be at the origin of four benign pathologies. The ombilicovesical fistula (47.6%) is diagnosed at the native period. In the adult, the most frequent form is the cyst (30.7%) whereas the external (16.4%) and internal sinus (3.2%) are rarer. Diagnosis depends on the clinical examination and the association of sonography and TDM. The risk of complications must systematically result in proposing a surgical treatment for these benign pathologies. The umbilicus resection is not recommended, but the surgeon has to remove the urachus and its implantation base on the bladder. Laparoscopic surgery seems to be an interesting route for this intervention.

Anatomical development of the normal urachus during the fetal period.

OBJECTIVE: To evaluate the development of the normal urachus during the fetal period. METHODS: The study was carried out on 149 human fetuses (male 87, female 62) aged between 9-40 weeks, obtained with families' consent from Isparta Maternity and Children's Hospital, Isparta, Turkey, between 1997 and 2002. The study was carried out in the Department of Anatomy, Faculty of Medicine, Suleyman Demirel University, Isparta, Turkey during 2004. The type of the urachus was assessed and was classified. The length, antero-posterior depth, and the transverse width of the urachus were measured. Finally, the relationship between the urachus and umbilical arteries was evaluated during the fetal period, whether they ran parallel to each other. RESULTS: Two types of urachus were observed: the inverted funnel (84%) and tubular (16%). The length, depth, and width of the urachus increased with gestational ages in all cases. A 2% variation was observed in the neighborhood between urachus and umbilical artery. CONCLUSION: Comparing our results with previous studies, the development of the urachus can be different in neonates and children. The mean urachus length was 14.8 -/+ 7.7mm during this period. The inverted funnel type is the most common type in our study. Hence, there can be some differences in the relationship between the urachus and umbilical arteries. The data obtained in the present study can be used as base knowledge related to the development of the urachus, and for evaluating the urachus in utero pediatric urology, radiology, pediatric surgery, and fetopathology.

Squamous cell carcinoma of the urachus.

A 64-year-old man was admitted with complaints of abdominal pain and pollakisuria. A soft mass was palpable under his navel. Magnetic resonance imaging (MRI) revealed a 9 x 6 cm tumor, which was composed of a cystic lesion arising from the urachus and a solid mass component at the urinary bladder dome. Urine cytology specimens showed squamous cell carcinoma (SCC). Serum SCC level was increased and the tumor was removed surgically. Histological examination detected well-differentiated SCC, which had invaded the urinary bladder and the peritoneum. The patient has been followed up without recurrence for 6 months.

Persistência do uraco em gato: relato de caso / Urachal persistence in a cat: case report

Relata-se o caso de um gato que apresentava persistência do uraco, cujos principais sinais clínicos, iniciados apenas aos cinco meses de idade foram micção através da cicatriz umbilical, hiperemia da área circunvizinha e presença de uma fístula no centro do umbigo. A afecção foi diagnosticada mediante exames clínico, laboratorial, ultra-sonográfico e radiográfico, especialmente pela cistografia

It is reported a case of a cat presenting persistence of the urachal. The symptoms only began at five months of age. The diagnosis was confirmed by the clinical, laboratorial, ultrasonographic and radiographic exams, especially by the cystography

Congenital patent urachus associated with incomplete urethral duplication: a rare association.

Congenital patent urachus (CPU) is an uncommon anomaly. Blind incomplete urethral duplication is encountered more frequently than other types of urethral duplication (UD) in clinical practice. We describe a child with CPU in association with distal blind incomplete UD. A possible pathogenesis of this extremely rare coexistence is discussed.

Patent urachus with bladder eversion.

An infant was born at term after having received a diagnosis of omphalacele on prenatal ultrasound scan. She did not have an omphalacele but rather had a patent urachus with bladder eversion onto the abdominal wall. The remainder of the genitourinary tract was normal, and it was possible to pass a soft catheter through the urethra and out of the evaginated bladder. The prolapse was repaired without complications, and the infant recovered uneventfully. A voiding cystourethrogram and renal ultrasound scan were normal at 2 month follow-up. The embryology and malformations of the urachus are discussed, and the rare case reports of similar anomalies are reviewed.

[Urachal actinomycosis: apropos of a case]. / Actinomicosis uracal: a propósito de un caso.

The report a new case of infected urachal cyst. The embryologic origin of the urachus, its anomalies, clinical features, diagnosis and treatment are discussed with the case of a 51 years old man who presented an hypogastric mass with the diagnosis of urachal actinomycosis.

A study of the anatomic features of the duct of the urachus.

The urachus is an embryonic remnant resulting from involution of the allantoic duct and the ventral cloaca. Attaching the bladder dome to the umbilicus, this duct becomes progressively obliterated during fetal life. It may subsequently persist as different variants after birth, some regarded as normal, others as pathologic, due to incomplete closure. Six pediatric cases are reported here, and the literature on the embryology and anatomic basis of the duct is discussed. The urachus is present in nearly 100% of children at birth, with several possible shapes: tubular, fusiform or funnel. It gradually regresses and is found in only a third of adults. Its length varies from 1 to 15 cm. In our series 6 patients showed defective closure of the duct, including 3 with complete patency, 1 cyst, 1 diverticulum and 1 external sinus. Although rare, congenital pathology of the urachus requires a sound knowledge of the anatomy and embryology to distinguish normal forms from those subject to complications. It should be suspected with any lesion in the umbilical region and the appropriate treatment instituted.

A novel navel presenting as an umbilical polyp and urachal sinus associated with an epigastric cleft: a clue to anterior midline fusion defects.

Umbilical and periumbilical disorders may present with a diverse group of anomalies and reflect the developmental embryological events they result from. A rare occurrence in a newborn of an umbilicus with an umbilical polyp together with an urachal sinus associated with a supraumbilical abnormal skin area known as epigastric cleft is reported herein, to help to elucidate embryological steps of anterior midline fusion defects and urachal remnants.

Premature urachal closure induces hydroureteronephrosis in male fetuses.

PURPOSE: Congenital hydronephrosis is more common in male individuals. We investigate whether an alteration in fetal bladder function induced by premature urachal closure contributes to fetal hydronephrosis, consequently explaining this male predominance. MATERIALS AND METHODS: The urachus was clipped in 8 male and 4 female ovine fetuses at 95 days of gestation (term 140 days). Subjects were sacrificed, and the urinary tract was assessed at 109 and 116 days of gestation in 3 and 1 male fetuses, respectively, and at term in 4 male and 4 female lambs. RESULTS: At 109 and 116 days of gestation 3 of the 4 male fetuses had upper tract dilatation. At term no female but 4 male lambs had hydroureteronephrosis, including some with marked pelvic dilatation and parenchymal thinning. At term mean bladder weight in the male animals with urachal clipping was 5.28 gm. (range 3.5 to 8.2), which was significantly greater than normal (p = 0.02). Bladder weight at term in the female lambs with urachal clipping was not different from normal values. Histological evaluation of the kidneys in the male lambs revealed cortical thinning and loss of medullary tissue, while the overall renal architecture was well preserved. CONCLUSIONS: Our observations indicate that normal ovine fetal urinary tract function and drainage depend on urachal function and the timing of urachal closure. Therefore, fetal hydronephrosis is associated with this alteration in bladder function but it may also be associated with other factors, such as bladder sphincter maturation or prostate development. Our experiment shows that hydroureteronephrosis develops in ovine fetuses when all bladder drainage occurs via the urethra. This condition may be an amplification of the differences in bladder outlet resistance in human fetuses, which may explain the male predominance in the various forms of hydroureteronephrosis.

Pediatric umbilical problems.

After birth, the normal umbilicus is a relatively simple structure. During the development of the embryo, however, this region is highly complex. Vestigial of the umbilical cord can be responsible for umbilical inflammation and drainage. This article reviews the embryology of the umbilicus and discusses a number of clinical problems seen in this area. The authors' aim is to aid the primary care pediatrician in evaluating, treating, and appropriately referring umbilical problems encountered in office practice.

Anomalías del uraco: informe de 10 casos / Abnirmalities of the urachus: report of ten cases

Las anomalías del uraco son raras y generalmente se manifiestan en la infancia. La presentación sintomática en el adulto es todavía menos frecuente, y en la literatura mundial se han informado sólo unos 370 casos. En este artículo se presentan diez casos de anomalías del uraco en edad pediátrica: cuatro quistes, cinco uracos permeables y una extensión uracal. Se revisa la embriología de esta estructura única a conjunto para entender las anomalías del desarrollo, y se describen las cuatro variantes anatómicas del uraco normal, que son de gran utilidad para comprender las variaciones congénitas y el tratamiento quirúrgico establecido. Se realiza la presentación separada de los casos por su importancia y el escaso número de los mismos, haciendo énfasis en el tratamiento quirúrgico individualizado.

The principles of normal and abnormal hindgut development.

In the past, several theories have been proposed to explain the occurrence of anorectal malformations. Most investigators believe that these malformations are the result of an impaired process of septation. However, in 1986 vd Putte challenged all theories that tried to explain anorectal malformations by a faulty fusion of lateral ridges of the cloaca. To elucidate the principles of normal and abnormal cloacal development, the authors studied the morphology of this region in normal embryos of rats and abnormal embryos of SD mice, which often have abnormal cloacas. Using scanning electron microscopy (SEM), 245 normal rat embryos and 80 abnormal SD-mice embryos were observed. The results were as follows. (1) In normal embryos the region of the future anal opening can be identified soon after the establishment of the cloacal membrane. This part is a fixed point in cloacal development. (2) In abnormal embryos the cloacal membrane is too short. The region of the future anal opening is missing. (3) In abnormal embryos a spectrum of malformed cloacas can be observed. This is in accordance with the spectrum of anorectal malformations clinically observed in humans. (4) The authors' observations support recent findings that the "fistula" in anorectal malformations resembles a normal anus at an ectopic position.

Anatomic basis of pathology of the urachus.

The urachus, derived partly from the allantoic canal, tethers the apex of the bladder to the umbilical ring. This vestigial structure, though constant in man, is formed by a whole series of embryologic mechanisms which are still controversial. Total or partial persistence of the lumen of the urachal canal, when sufficiently extensive, becomes manifested by characteristic clinical features. Moreover, it is frequently associated with malformational urogenital involvement, which must be routinely sought. The sole form of treatment consists of total surgical excision of the urachus.

Infected urachal remnants in the adult: case report and review.

Abnormalities of the urachus in adults are uncommon. Urachal tract remnants that abnormally remain patent are subject to infection. Urachal infection is frequently confused with a wide spectrum of midline intraabdominal or pelvic inflammatory disorders. Because the literature on urachal infection is primarily limited to articles in urology and surgical specialty journals, many physicians may not be familiar with the varied clinical manifestations. We describe a case of infection of a patent urachus in an adult and review the embryology and anatomy of the urachus as it relates to clinical presentation, evaluation, and management. Infection of a urachal remnant should be included in the broad differential diagnosis of omphalitis and midline abdominal or pelvic infections. Rarely, it may be a cause of recurrent urinary tract infection. Definitive management consists of surgical excision after the institution of antimicrobial therapy.