A 17-year-old Hispanic adolescent boy presented to the emergency department with a 6-hour history of right ﬂank pain and hematuria. Recently, in a South American country, he had had a diagnosis of bilateral hydronephrosis and a right orchiectomy for an undescended testis.
Christopher Wen, MD
Allen J. Cohen, PhD, MD
from the Department of Radiological Sciences; and
Dorothy J. Marquez, MD
from the Department of Medicine, University of California, Irvine
Medical Center, Orange, CA.
A 17-year-old Hispanic adolescent boy presented to the emergency
department with a 6-hour history of right flank pain and hematuria.
Recently, in a South American country, he had had a diagnosis of
bilateral hydronephrosis and a right orchiectomy for an undescended
testis. Laboratory results were remarkable for a white blood cell
count of 11,000 and a urine analysis of 2+ white blood cells and 50
red blood cells/high-power field. The serum creatinine was 1.1
mg/dL. The clinicians suspected pyelonephritis, and a noncontrast
computed tomography (CT) scan of the abdomen and pelvis was
performed (Figure 1). An intravenous urogram (IVU) was also
obtained 12 days later (Figure 2). The patient was seen in the
urology clinic, where a physical examination found a descended left
testis and an empty right hemiscrotum. The patient was treated with
antibiotics for a urine culture positive for
Eagle Barrett Syndrome (also known as prune-belly syndrome
[PBS]) in an adult
Noncontrast CT scan of the abdomen shows massive hydronephrosis,
with the right kidney worse than the left (Figure 1A), marked
bilateral redundant hydroureter, a thick-walled bladder, and absent
abdominal wall musculature (Figure 1B). A postvoid film from an IVU
showed a poorly functioning right kidney with a massive renal
pelvis and marked left hydronephrosis and redundant hydroureter
Prune-belly syndrome is a congenital disorder characterized by
the clinical triad of cryptorchidism, hypoplasia of the abdominal
musculature, and abnormalities of the urinary tract. The term
"prune belly" reflects the characteristic wrinkled appearance of
the abdominal wall in the newborn due to the complete or partially
complete absence of abdominal wall muscles. In adolescent and adult
life, the abdomen often assumes a smooth "pot-belly" configuration.
In the United States, the incidence of PBS is 1 in 35,000 to 50,000
live births; it occurs in all races. There are other associated
anomalies, including clubfoot, intestinal malrotation, pulmonary
dysplasia, congenital hip dislocation, and cardiac defects due to
the sequela of oligohydraminos in utero.
Ninety-five percent of cases occur in males. Diagnosis is made in
utero using ultrasound (US) or in the neonate with characteristic
clinical findings. The diagnosis is suspected in the fetus when US
imaging reveals an enlarged bladder, dilated ureters, and an
abnormal abdominal wall. However, the same constellation of US
findings can be caused by posterior urethral valves (PUV) with
severe hydroureteronephrosis. Amniotic fluid volume may be normal
or decreased in neonates with PBS. Occasionally, PBS can be seen in
older children or adults with renal failure, recurrent infections,
Morbidity relates to the degree of dilation of the urinary
tract, in which poor ureteral peristalsis and weak forward
propulsion of urine in the ureters results in stasis, infection,
and stone formation. Renal failure results from underlying renal
dysplasia and the aforementioned complications of urinary stasis.
Twenty percent of patients are stillborn, 30% die of renal failure
or urosepsis within the first 2 years of life, and the remaining
50% have varying degrees of urinary pathology.
In the 1970s, half of the patients with PBS died in early
infancy. Currently, the survival rate has improved markedly. The
severe abdominal distention also is marked by pulmonary hypoplasia
related to the patient's large abdominal contents and compromise of
the thorax during fetal development.
Older theories postulated that lower urinary tract obstruction
at the level of the prostate caused overdistension of the bladder.
In turn, hydroureter and hydronephrosis developed. The mass effect
from the dilated upper urinary tract interfered with descent of the
testes and development of abdominal wall musculature.
Newer hypotheses ascribe the syndrome to a gestational insult
disrupting mesodermal development. Embryogenesis of the abdominal
wall musculature and lining of the genitourinary tract are
The genetic basis of PBS is uncertain. An X-linked defect is
suggested by the predominance of affected males. However, females
can be affected, casting doubt upon this observation.
Hydronephrosis and varying degrees of renal dysplasia are
present in >50% of cases. There may be clubbing of the calyces,
narrowing of infundibula, and cyst formation. The ureters often
exhibit gross dilation, elongation, and tortuosity due to
replacement of smooth muscle with fibrous tissue. The distal ureter
is more affected than the proximal ureter. Often, the bladder is
enlarged and nontrabeculated because of the replacement of smooth
muscle by collagen. It can be elongated and attached to a patent
urachus or urachal diverticulum superiorly. The prostate is
markedly hypoplastic, leading to dilation of the prostatic urethra.
The anterior urethra is abnormal in 70% of cases, often in the form
of a scaphoid megalourethra. Females can have urethral atresia.
Virtually all males have bilateral undescended testes. Females
usually have normal ovaries, but abnormalities of the uterus and
Historically, the diagnosis was made based on: 1) physical
examination; 2) a chest radiograph showing hypoplastic lungs and
distended flanks; and 3) IVU findings of dilated and clubbed renal
calyces, markedly dilated and tortuous ureters, and a large
vertical trabeculated bladder. Radiologic findings in PBS that
distinguish it from PUV include greater dilation and redundancy of
the distal thirds of the ureters and anterior urethral
In some rare cases, urethroscopy may be necessary to differentiate
these entities. With the increasing use of noncontrast CT to
evaluate the genitourinary system, awareness of the appearance of
PBS on CT is important.
TREATMENT AND PROGNOSIS
The prognosis depends on the severity of the abnormalities. The
presentation can range from stillborn fetuses to older children
with recurrent infections and renal insufficiency. Orchiopexy is
required due to the increased risk of malignancy in undescended
testes. Repair of the abdominal wall musculature is not simply
cosmetic, as it plays an important role in pulmonary, bladder, and
intestinal function and is crucial in the surgical management of
The diagnosis of PBS should be made in an adult whose CT scans
show renal hypoplasia, hydronephrosis, redundant hydroureter, and
deficient anterior abdominal musculature.