Neurofibromatosis is a group of inherited developmental disorders of the nervous system, muscles, bones, and skin that causes formation of multiple, pedunculated, soft tumors (neurofibromas), and café-au-lait spots. The most common types are NF-1 (von Recklinghausen disease) and NF-2 (bilateral acoustic neurofibromatosis). About 80,000 Americans are known to have neurofibromatosis; in many others, the disorder is overlooked because symptoms are mild. The prognosis varies; however, spinal or intracranial tumors can shorten the patient's life span.
NF-1 is an autosomal dominant disorder of chromosome 17 that occurs in about 1 in 3,000 births. Approximately 50% of affected families have a negative family history; in many of these families, the father is older, suggesting that advanced paternal age may influence the NF-1 mutation. NF-2 is an autosomal dominant disorder of chromosome 22; however, many patients have a negative family history.
Signs and symptoms of NF-1 vary greatly from one family to another and within members of the same family. A patient with seemingly mild symptoms initially may develop more severe problems later.
An infant with this form may present with only café-au-lait spots or may also have congenital glaucoma, plexiform neurofibromas, or pseudoarthrosis. About 90% of patients have Lisch nodules on the iris; as many as 15% develop optic pathway gliomas, which may cause a significant loss of vision.
Cutaneous and other neurofibromas may begin to develop or become more prominent at puberty; pregnancy may exacerbate tumor growth. Some tumors become malignant; approximately 8% of patients develop neurofibrosarcoma (cancer of the nerve sheath). Other less-specific features may include other types of tumors (such as meningiomas), short stature, seizures, speech and learning disabilities, mental retardation (occasionally), and abnormalities of the cerebral, GI, and renal arteries.
The first sign of NF-2 is usually a central nervous system tumor, such as a spinal or intracranial meningioma, an acoustic neuroma, and occasionally a schwannoma or spinal astrocytoma. Cutaneous neurofibromas may be less conspicuous in this form, and café-au-lait spots may be minimal or even absent. Learning disabilities and other less-specific features characteristic of NF-1 aren't typically seen in NF-2.
Diagnosis rests on typical clinical findings, especially neurofibromas and café-au-lait spots. Diagnostic criteria for NF-1 include two or more of the following:
❑ first-degree relative (parent, sibling, child) with known NF-1
❑ six or more café-au-lait spots over 5 mm in diameter in a prepubertal patient and 15 mm or more in a postpubertal patient
❑ freckling in the axillary or inguinal region
❑ optic pathway glioma
❑ two or more Lisch nodules on the iris
❑ osseous lesion, such as sphenoid dysplasia or thinning long-bone cortex.
Diagnostic criteria for NF-2 include a first-degree relative with NF-2 and two of the following:
❑ neurofibroma, meningioma, schwannoma, glioma, juvenile posterior subcapsular lenticular opacity
❑ unilateral eighth nerve mass
❑ bilateral eighth nerve masses seen on magnetic resonance imaging (MRI) or computed tomography (CT) scan.
X-rays, MRI, and CT scan may be indicated to determine the presence of widening internal auditory meatus and intervertebral foramen. An eye examination to look for Lisch nodules should be done on patients suspected of having NF-1. Myelography may be used to identify spinal cord tumors, and lumbar puncture with cerebrospinal fluid analysis will reveal elevated protein concentration in the presence of spinal neurofibromas and acoustic tumors. Deoxyribonucleic acid analysis and prenatal diagnosis may also be done in some families.
Neurofibromatosis has no specific treatment. Management consists of surgical removal of intracerebral or intraspinal tumors (when possible) and correction of kyphoscoliosis. Tumors that cause pain and loss of function are removed on an individual basis.
Cosmetic surgery for disfiguring or disabling growths may be done; however, regrowth is likely. Special schooling for individuals with learning disorders or attention deficit hyperactivity disorder may be required. Annual eye exams should be performed.
Researchers are currently investigating experimental treatments for severe tumors.
❑ Disfigurement may cause overwhelming embarrassment and social regression. By showing acceptance, you can help the patient adjust to his condition.
❑ Advise the patient to choose attractive clothing that covers unsightly nodules; suggest special cosmetics to cover skin lesions.
❑ Refer the patient for genetic counseling to discuss the 50% risk of transmitting this disorder to offspring. Recommend contacting the National Neurofibromatosis Foundation.
Review other book chapters online related to Neurofibromatosis:
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Professional Guide to Diseases (Eighth Edition) Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2005 ISBN: 1-58255-370-X 
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