Juvenile Intestinal Polyposis Syndrome

At a glance

It is a familial noncancerous polyposis of the colon characterized by abdominal pain, rectal bleeding, and diarrhea. People with this medical condition typically develop polyps before age 20. Approximately 15% of those affected with this condition present other abnormalities such as intestinal malrotation, heart or brain defects, cleft palate, polydactyly of the hands and toes, and urogenital abnormalities. It is estimated that people with Juvenile Polyposis Syndrome have between 10 and 50% risk of developing a malignancy of the gastrointestinal tract. Colorectal cancer is the most common type.

Synonym

Juvenile Polyposis Syndrome.

Classification

Three types of Juvenile Polyposis Syndrome are described and are based on the signs and symptoms.

• Juvenile Polyposis of Infancy: Characterized by the presence of gastrointestinal polyps during infancy. It is the most severe form of the disorder and is associated with the worst outcome. These infants may develop a condition called protein-losing enteropathy. This condition results in severe diarrhea, failure to thrive, severe anemia, and general cachexia.

• Generalized Juvenile Polyposis: Diagnosed when polyps are present throughout the gastrointestinal tract. It typically develops during childhood.

• Juvenile Polyposis Coli: Characterized when polyps are only present within the colon. It typically develops during childhood.

Incidence

Solitary juvenile polyps occur in 1% of children, but juvenile polyposis is much rarer.

Genetic inheritance

This condition is associated with both familial and nonfamilial polyposis. A family history of juvenile polyposis is present in 20 to 50% of patients. Autosomal dominant inheritance has been reported. There is evidence that a mutation in the SMAD4/DPC4 gene located on 18q21.1 result in juvenile polyposis. Juvenile polyposis may be associated with mutations in the PTEN gene (possible gene map location 10q23.3).

Pathophysiology

Patients have a variable number of polyps, usually between 50 and 200, distributed throughout the gastrointestinal tract, most commonly in the colon.

Diagnosis

Juvenile polyps are distinctive both macroscopically and histologically. They are usually pedunculated and spherical with a smooth surface within which are numerous large cystic spaces of variable size, filled with grayish or yellowish mucus surrounded by copious reddish stroma. In contrast to the hamartomatous polyps of Peutz-Jeghers Syndrome, muscle fibers are not present in the stroma.

Clinical aspects

Usually present in childhood; less than 15% present in adulthood. Classified into three groups:

• Juvenile Polyposis of Infancy: Presents with diarrhea, hemorrhage, intussusception, rectal prolapse, and protein-losing enteropathy; entire gastrointestinal tract is affected, prognosis related to severity and extent of gastrointestinal involvement); usually fatal before 2 years of age.

• Generalized Juvenile Polyposis: Diagnosed when polyps are present throughout the gastrointestinal tract. It typically develops during childhood.

• Juvenile Polyposis of the ...