• Hirschsprung disease
• “Small round cell” tumors
• Congenital malformations including cardiac and other systems
• Placental pathology
• Electron microscopy and biochemical studies
of metabolic
disorders, immunohistochemistry, and advanced molecular diagnosis.
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Hirschsprung disease (congenital megacolon) is a congenital condition
due to absence of ganglion cells in the submucosal and myenteric plexuses
of the bowel. It occurs as a result of abnormalities in the migration
and/or development of ganglion cells.
Hirschsprung disease is a common (1 in 5,000 live births) abnormality
that results in intestinal pseudo-obstruction because a segment (of
variable length) of bowel does not move normally. It is most often found
in males, and it is commonly seen in children with Down syndrome. The
degree of severity ranges from a life-threatening condition requiring
emergency surgery, to a chronic disorder. Some cases are familial (hereditary).
The
area lacking ganglion cells acts as a blockage in the colon. Surgery
to remove the abnormal segment is needed at once. Without surgery the
large
intestine may rupture.
In a newborn, the chief signs and symptoms are failure to
pass a meconium stool within 24-48 hours after birth, reluctance to
eat,
bile-stained
(green) vomiting, and abdominal distension. During infancy the
child has difficulty gaining weight, constipation, abdominal distension,
episodes of diarrhea and vomiting. In older children, symptoms
become
chronic and include constipation, passage of ribbon-like, foul-smelling
stools, abdominal distension and visible peristalsis (wave-like
movement of the intestines). The older child is usually poorly
nourished and
anemic.
To diagnose Hirschprung disease, a rectal biopsy is absolutely required.
Treatment of the disease requires the removal of the abnormal (aganglionic)
portion of colon.
Surgical correction is a 1 to 3 stage procedure. An
appropriate microscopic evaluation of the abnormal colon by a trained
pediatric
pathologist is essential to ensure an adequate outcome. In
some cases, a temporary colostomy (an artificial opening from the
colon to the
skin) is placed within a portion of normal bowel to allow adequate
excretory function, providing the child with time for weight
gain before the more complicated repair takes place at the following
surgical step.
In the final correction, the pediatric surgeon pulls the working
part of the colon down and attaches it to a point near the
anus. The colostomy
may be closed at this time.
