NEUROFIBROMATOSIS (continued) Diagnosis
A family history is obtained in over 50% of patients. In type 1, the cutaneous manifestations are characteristic, though they may be extremely mild with only café au lait spots (more than 6 in an individual is diagnostic). As a rule, the more florid the cutaneous manifestations the less likely is there nervous system involvement. CT scanning, MRI and myelography may be necessary when nervous system involvement is suspected. Type 2 is diagnosed when imaging (MRI) confirms bilateral vestibular schwannomas. The recent cloning of the type 2 gene to chromosome 22 may lead to direct gene testing in persons at risk.
Plexiform neuromas may be removed for cosmetic reasons. The management of intracranial and intraspinal tumours has already been discussed.
Incidence: 1:30 000.
Autosomal dominant inheritance with high sporadic mutation rate. Linkage studies suggest a locus on chromosome 9.
Characterised by cutaneous, neurologic, renal, skeletal, cardiac and pulmonary abnormalities. Pathology
Hard gliotic 'tubers' arise anywhere within the hemisphere but commonly around the ventricles. Projection into the ventricles produces a typical appearance like 'dripping candle wax'.
Tubers in the brain result from Transition may occur astrocytic overgrowth with large from gliosis to a vacuolated cells and loss of subependymal surrounding myelin. astrocytoma.
As well as skin lesions, primitive renal tumours and cystic lung hamartomas occur.
The cutaneous lesions are characteristic - adenoma sebaceum, a red raised papular-like rash over the nose, cheeks and skin, appears towards-------------
the end of the 1st year, though occasionally as late as the 5th year. Depigmented areas on the trunk resembling vitiligo are common. Fibromas and café au lait spots occur occasionally.
Neurological manifestations'. - Mental retardation is present in 60% of patients, though the onset and its recognition may be delayed.
Seizures occur in almost all patients, often as early as the 1st week of life. Attacks are initially focal motor and eventually become generalised. The response to anticonvulsants is variable.
Intracranial neoplasms - astrocytomas - arise from tubers usually close to the ventricles and may result in an obstructive hydrocephalus.
Neoplasia: - Renal carcinoma occurs in 50% of patients. Retinal tumours (hamartomas) and muscle tumours (rhabdomyomas) are common, the latter often involving the heart.
The presence of epilepsy and adenoma sebaceum is diagnostic.
CT scan may show subependymal areas of calcium deposition. MRI shows uncalcificd subependymal tubers. Other developmental abnormalities may be evident, e.g. microgyria.
Anticonvulsant therapy for epilepsy. Surgical removal of symptomatic lesions.
Was this article helpful?
This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.