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Neurofibromatosis, Type 2
		Uploaded: 2007-11-16, Updated: 2007-11-16

CLINICAL FEATURES
	Also called central neurofibromatosis, MISME syndrome or neurofibromatosis with bilateral acoustic neuromas. Affects 10% of NF patients. In the US: incidence of NF2 is 1/30,000-40,000.
GENETIC MUTATIONS
	NF-2 gene: location, 22 (22q12.2); gene product: merlin or schwannomin, a tumor suppressor. In most cases the mutation in the NF II gene causes shortened peptides. Patients with frame-shift mutation or nonsense mutations suffer poor prognosis. Patients with missense mutations have a better prognosis.
DIAGNOSTIC CRITERIA
	Definite diagnosis of NF2
	Bilateral CN VIII schwannomas on MRI/CT scan (no biopsy necessary) First-degree relative with NF2 and either unilateral early-onset CN VIII schwannoma (age <30 y) or any 2 of the following: Meningioma Glioma Schwannoma Juvenile posterior subcapsular lenticular opacity (juvenile cortical cataract)
	Presumptive diagnosis of NF2
	Early onset of unilateral CN VIII schwannomas on MRI/CT scan in patients <30 years and one of the following: Meningioma Glioma Schwannoma Juvenile posterior subcapsular lenticular opacity Multiple meningiomas (>2) and unilateral CN VIII schwannoma or one of the following: Glioma Schwannoma Juvenile posterior subcapsular lenticular opacity
PATHOLOGY FINDINGS
	Acoustic nerve: 90% of the patients show bilateral acoustic neuromas on MRI. Other intracranial lesions: in about 50% of patients, schwannomas and meningiomas. Spinal cord: About 50% of the patients develop spinal lesions. Intramedullary lesions: spinal astrocytomas or ependymomas; Extramedullary lesions: schwannomas of dorsal nerve root and meningiomas. Skin: 70% patient have cutaneous schwannomas. Eyes: > 90% patients suffer eye lesions, mostly juvenile subcapsular cataract (opacity of the lens).
REFERENCES
	AFIP, tumor of the central nervous system, series 4 http://www.emedicine.com/neuro/topic248.htm http://en.wikipedia.org/wiki/Neurofibromatosis_type_I