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The most common gastrointestinal tumor in children is the benign
single juvenile polyp. Single juvenile polyps are relatively common
and do not infer an increased risk of colorectal cancer at any age. In
contrast, findings of 5 or more hamartomatous polyps, one or more
adenomas, or abnormal dysplastic histology suggest a diagnosis of
one of the rare hereditary colorectal cancer syndromes. A family history
of early cancer or polyps affecting multiple relatives over several
generations is also consistent with a hereditary cancer syndrome.
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The manifestations or expression of hereditary colorectal cancer/polyposis
syndromes can be highly variable within a given family. Most of
these syndromes are autosomal dominant, with cancer-related symptoms
expected in other family members. The age of presentation, polyp
number, and distribution or the age of cancer development can differ
among affected family members who carry the same gene mutation.
New spontaneous germline mutations are seen in up to one third of
newly diagnosed pediatric polyposis patients.
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Adenomas are either sessile or pedunculated and can be difficult
to differentiate from hamartomas by appearance at endoscopy. Adenomas are
by definition dysplastic having disorganized epithelial proliferation,
loss of goblet cells, cellular and nuclear atypia. Dysplasia proceeds from
mild to severe with further loss of cell growth regulation and indicates
the progression from adenoma to early adenocarcinoma. Polyps can
have mixed histologic features of both hamartomas and adenomas. Finding
an adenomatous polyp in a child or adolescent suggests the diagnosis
of a hereditary adenomatous polyposis syndrome, all of which are
associated with a substantial risk of colon or other cancers, so
further evaluation and surveillance are mandatory.
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Juvenile polyps are the most common gastrointestinal tumor during
childhood and can be seen in up to 2% of children under
the age of 10 years.1,2 These lesions can present
with painless rectal bleeding during defecation, or may only present
when the polyp prolapses through the anus. Colonic juvenile polyps
can also present with colic-like abdominal pain, diarrhea, or unexplained
iron deficiency anemia. Juvenile polyps typically present from 2
to 4 years of age but can be found at any time during childhood
or adolescence. Most juvenile polyps are solitary and are found
in the rectosigmoid colon. Smaller polyps appear as flat sessile
mucosal elevations that with time grow into mushroom-like pedunculated
lesions. Juvenile or inflammatory polyps are classified as hamartomas.
Pathology reveals an overgrowth of mature orderly epithelium with
dilated mucus-filled glands, varying numbers of inflammatory cells,
and surface ulceration. At times, the inflammation seen in juvenile
polyps described as reactive atypia can be indistinguishable from
early dysplasia.
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Juvenile Polyposis
Syndrome
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The diagnostic criteria for juvenile polyposis syndrome (JPS)
include: the cumulative development of 5 or more colonic juvenile
polyps; the presence of juvenile polyps in the stomach or small
intestine (excluding other polyposis syndromes); or the presence
of any juvenile polyp with a positive family history of JPS.3,4...