Other Rare Childhood Cancers
Multiple Endocrine Neoplasia Syndrome
Skin Cancer (Melanoma, Basal Cell Carcinoma, Squamous Cell Carcinoma)
Chordoma
Cancer of Unknown Primary Site
Other rare childhood cancers include multiple endocrine neoplasia syndrome, skin cancer, chordoma, and cancer of unknown primary site. These other rare childhood
cancers are discussed below.
Multiple Endocrine Neoplasia Syndrome
Multiple endocrine neoplasia syndromes or MEN (abnormal and uncontrolled cell growth) are familial disorders that include cancerous changes in more than one endocrine organ at the same time (endocrine tissue secretes hormones). These changes may
include hyperplasia (overgrowth of tissue) or benign (noncancerous) tumors.
These disorders, called MEN 1, MEN 2A, and MEN 2B, are caused by abnormal genes. Patients and family members at risk for these syndromes should have both genetic testing and physical examinations.
MEN 1 (Werner syndrome) may involve tumors of the pituitary gland and parathyroid, adrenal, gastric, and pancreatic structures.
MEN 2A (Sipple
syndrome) is associated with medullary thyroid carcinoma, parathyroid
hyperplasia, and adenomas as well as pheochromocytoma; MEN 2B is associated
with medullary thyroid carcinoma, parathyroid hyperplasia, and adenomas as well
as pheochromocytoma, mucosal neuromas, and ganglioneuromas. An additional
complex is referred to as the Carney complex, which is associated with benign tumors of the heart, skin, breast, head or neck.
Patients with the MEN 2A syndrome usually have surgery to remove the thyroid by the age of 5 years or at the time genetic changes are found in order to prevent cancer. Family members of patients with the MEN 2A syndrome should be tested in early childhood, before age 5, for the abnormal gene that leads to this type of cancer. If they are found to have this genetic change, they should have surgery to remove the thyroid and replace it with a transplant of one of their own parathyroid glands by a certain age.
Patients with the MEN 2B syndrome may have a slender body build, long and thin
extremities, a high arch palate, and “funnel chest” (sunken chest) or an abnormally high arch in the foot. The lips may appear thickened because of tumors in the mucous membranes. In this
syndrome, medullary thyroid cancer may be particularly aggressive; therefore,
the thyroid should be removed in infancy to prevent cancer in these affected children.
Hirschsprung disease (a condition present at birth that causes blockage of the large intestine due to lack of muscle contractions) is also associated with medullary thyroid carcinoma. Patients with Hirschsprung disease should be screened for genetic changes that may be linked to this cancer. If such changes are found, surgery to remove the thyroid in order to prevent cancer may be considered.
The outcome for patients with the MEN 1 syndrome is generally good, provided
adequate treatment can be obtained for parathyroid, pancreatic, and pituitary
tumors. The outcome for patients with the MEN 2A syndrome is also generally
good, but the possibility exists for recurrence of medullary thyroid carcinoma
and pheochromocytoma. Medullary thyroid cancer in children with MEN 2B may be difficult to cure. For patients with the Carney complex, prognosis depends
on how often heart, skin, or other tumors recur.
Treatment of medullary thyroid carcinoma may include a clinical trial of a tyrosine kinase inhibitor, a drug that interferes with cell communication and growth and may prevent tumor growth, taken by mouth.
Skin Cancer (Melanoma, Basal Cell Carcinoma, Squamous Cell Carcinoma)
Melanoma is thought to be the most common skin cancer in children, followed by basal cell and squamous cell carcinomas. The incidence of melanoma in children
and adolescents represents approximately 1% of the new cases of melanoma that
are diagnosed annually in the United States. Melanoma is most often found in children aged 10 years or older, and is slightly more often found in girls than boys. In most instances, melanoma in the pediatric population is similar to that of adults in relation to site of
presentation, symptoms, description, and spread, although thickness does not seem to predict how likely it is to be cured. Melanoma may grow faster in children than in adults. In most children and adolescents, melanoma is found as localized cancer with no sign of spread and can usually be cured. In children and adolescents with melanoma that has spread to the lymph nodes or distant parts of the body, the prognosis appears to better than the prognosis for adults with melanoma in similar stages. The reason for this difference is not known.
The most common cause of skin cancer of any type is exposure to the ultraviolet (UV) portion of sunlight. Other causes may be related to chemical carcinogenesis, radiation exposure, immunodeficiency, or immunosuppression. The person who is most likely to develop a melanoma is easily sunburned, has
poor tanning ability, and generally has light hair, blue eyes, and pale skin.
Worldwide, there is an increasing incidence of both melanoma and nonmelanoma
skin cancers. Melanoma presents as a relatively flat, dark-colored lesion that may enlarge, penetrate the skin, or metastasize.
Melanomas may be congenital (present at birth). They are sometimes associated
with large congenital black spots known as melanocytic nevi, which may cover
the trunk and thigh. Children with hereditary immunodeficiencies have an
increased lifetime risk of developing melanoma.
Individuals with atypical moles, which include raised lesions (that may or may
not bleed) and various color hues (brown, tan, pink, black) are at an increased
risk of having melanoma and having children affected by these premalignant lesions. Basal cell carcinoma generally appears as a raised lump or ulcerated lesion, usually in areas with previous sun exposure. Squamous cell carcinomas
are usually reddened lesions with varying degrees of scaling or crusting; they
have an appearance similar to eczema, infections, trauma, or psoriasis.
Basal and squamous cell carcinomas are generally curable with surgery alone,
but the treatment of melanoma requires greater consideration because of its
potential for metastasis. Surgery for melanoma depends on the size, site,
level of invasion, and metastatic extent or stage of the tumor. If the melanoma has not spread beyond the lymph nodes, adjuvant biologic therapy may be given to increase the chances of a cure. If the melanoma has spread beyond the lymph nodes, treatment may include a combination of chemotherapy and biologic therapy. There are clinical trials for melanoma available to children aged 10 years or older. Information about ongoing clinical trials is available from the NCI Web site.
Chordoma
Chordoma is a very rare type of bone tumor that may develop along the spine at any point from the base of the skull to the tailbone. Chordomas start in clusters of cells leftover from spinal column development in the embryo. These cells normally disappear, but very rarely they remain and grow into tumors. In children and adolescents, especially girls, chordomas often develop in the clivus, a bone at the base of the skull. Symptoms vary and may include pain and nerve trouble. When chordoma recurs, it usually comes back in the same area, but may appear in the lungs or other areas of bone.
Standard treatment includes surgery and radiation therapy. The best results are seen with proton beam therapy, a special kind of high-energy radiation that is different from an x-ray.
Cancer of Unknown Primary Site
Cancer can form in any tissue of the body and can spread from the primary site (the place where the cancer first began to grow) to other parts of the body. Cancer that has spread from the place in which it started to other parts of the body is called metastatic cancer. Metastatic cancer cells usually look like cells in the type of tissue where the cancer began. For example, breast cancer cells that spread to the lung look like breast cancer cells, not lung cancer cells. Sometimes metastatic cancer cells are found in the body, but tests do not find a primary tumor. If cancer cells are found in the body but the place where the cancer started cannot be identified, the disease is called cancer of unknown primary site. Treatment is based on what the cancer cells look like under a microscope, the patient's symptoms, and the extent of the cancer in the body. Treatment is usually chemotherapy or radiation therapy.
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