AUTHOR AND EDITOR INFORMATION

Section 1 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT Scan
• MRI
• Angiography
• Intervention
• Multimedia
• References

INTRODUCTION

Section 2 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT Scan
• MRI
• Angiography
• Intervention
• Multimedia
• References

Background

Neurofibromatosis 2 (NF2) is an inherited autosomal dominant syndrome characterized by multiple schwannomas, meningiomas, and ependymomas.^{1, 2} The most common tumor associated with the syndrome is the vestibulocochlear (cranial nerve [CN] VIII) schwannoma, and as many as 10% of patients with this tumor have NF2. Although it shares a name with neurofibromatosis type 1 (NF1; von Recklinghausen disease), the 2 diseases are separate entities. Neurofibromas are rarely found in NF2, which has led some to propose that the disease be termed schwannomatosis or MISME syndrome, the acronym for the following terms:

• Multiple inherited schwannomas
• Meningiomas
• Ependymomas

The term MISME has become used widely as a mnemonic to remember the disease.

Although a presumed case of NF2 was first described in 1882 by Wishart, the disease was not separated from von Recklinghausen disease until 1987, when it was demonstrated that the 2 disorders arose from different chromosomes. The genetic defect responsible for NF2 is a deletion of a portion of chromosome 22, the same chromosomal abnormality found in spontaneous spinal schwannomas, indicating that a single location causes Schwann cell tumor growth.^{3, 4, 5, 6}

In 1988, the National Institutes of Health released a conference statement regarding neurofibromatosis that addressed the diagnosis of NF2.⁷ The criteria that were chosen for the diagnosis of NF2 were the following, of which only 1 criterion was needed to make the diagnosis:

• Bilateral CN VIII masses seen with appropriate imaging techniques (eg, computed tomography [CT] scanning or magnetic resonance imaging [MRI])
• A first-degree relative with NF2 and either a unilateral CN VIII mass or 2 of the following:
• • Neurofibroma
  • Meningioma
  • Glioma
  • Schwannoma
  • Juvenile posterior subcapsular lenticular opacity

In the past 2 decades, a revision to these diagnostic criteria of NF2 was proposed that concerns the addition of a section for presumptive or probable diagnosis of NF2. These modified criteria are listed as follows⁸:

• Definite diagnosis of NF2
• • Bilateral CN VIII schwannomas on MRI or 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 or CT scan detected in patients younger than 30 years and 1 of the following:
  • • Meningioma
    • Glioma
    • Schwannoma
    • Juvenile posterior subcapsular lenticular opacity
  • Multiple meningiomas (>2) and unilateral CN VIII schwannoma or 1 of the following:
  • • Glioma
    • Schwannoma
    • Juvenile posterior subcapsular lenticular opacity

Baser et al studied 4 different sets of diagnostic criteria and concluded that none of them is adequate in diagnosing patients who do not have bilateral acoustic neuromas at the initial workup. The authors proposed that a single set of diagnostic criteria should be devised to supplant the 4 existing sets, although when or if this will occur is not certain.

Although CN schwannomas, except for CN VIII schwannomas, also occur spontaneously, they are relatively rare. Thus, the presentation of any patient with multiple CN schwannomas, an unusual intracranial schwannoma, or a single CN III (oculomotor), CN IV (trochlear), or CN VI (abducens) schwannoma should prompt screening for NF2. In addition, consider the diagnosis in the workup of patients with multiple extra-axial brain or spine tumors, regardless of whether they are meningiomas or schwannomas.

For excellent patient education resources, visit eMedicine's Cancer and Tumors Center. Also, see eMedicine's patient education article Understanding Lung Cancer Medications.

Related eMedicine topic:
Neurofibromatosis Type 1

Related Medscape topics:
Resource Center Genomic Medicine
Resource Center Head and Neck Cancer

Pathophysiology

Lesions of the brain and spine eventually occur in almost all patients with NF2. CN VIII schwannomas are the hallmark of the disease, but schwannomas can be found involving any CN from CN III to CN XII, with CN V (trigeminal) as the next most frequently involved. Spontaneously occurring CN VIII schwannomas have a similar appearance but typically occur later in life. Dural-based meningiomas are commonly seen in NF2 and are often multiple in number, occasionally seeding the meninges with tiny tumor foci.

Meningiomas found in NF2 resemble spontaneously occurring meningiomas in location and appearance, and although NF2 meningiomas are similar to vestibular schwannomas, they occur at an earlier age. Consider the diagnosis of NF2 in any patient younger than 30 years with meningioma or CN schwannoma.

Ependymomas are the most common intraparenchymal tumor in NF2, although gliomas are rarely associated with the syndrome and schwannomas rarely present as a solely intraparenchymal lesion. Multiple studies have described benign intracranial calcifications, particularly of the choroid plexus, cerebellar hemispheres, and cerebral cortex, in association with NF2.

Spinal tumors seen in NF2 include schwannomas, meningiomas, and ependymomas. Schwannomas may present as intradural extramedullary masses or may involve the exiting nerve roots. Nerve root tumors in NF2 may present as dumbbell-shaped lesions extending through the neural foramina, similar to the neurofibromas of NF1, but histology reveals that most of these are schwannomas.

Meningiomas present as intradural extramedullary masses that are similar to spontaneous meningiomas and typically involve the thoracic spine; they are often multiple in number. Most intramedullary spine tumors in NF2 are ependymomas and arise in either the upper cervical cord or the conus. Different genotypes in NF2 have been correlated with differing incidences of various spinal neoplasms: patients with frameshift and nonsense mutations have higher incidences of all spinal tumors but especially intramedullary tumors.

A few ocular abnormalities occur in NF2, including a form of early-onset cataract termed juvenile posterior subcapsular lenticular (or lens) opacity.^{9, 10, 11, 12, 13} Hamartomas of the retina and choroids are common in NF2, and a patient's vision may be affected by optic nerve (CN II) sheath meningiomas.

Although patients with NF2 may have cutaneous schwannomas that resemble skin tags, they rarely have café-au-lait spots and do not demonstrate the cutaneous neurofibromas that typically result in the early diagnosis of NF1. Because symptoms from CN VIII schwannomas usually begin in the third decade, patients with NF2 are typically diagnosed later in life than patients who have NF1.

Frequency

United States

The incidence of NF2 is approximately 1 per 30,000-40,000 persons.

International

The incidence of NF2 is approximately 1 per 30,000-40,000 persons.^{14, 15}

Mortality/Morbidity

Hearing loss resulting from CN VIII schwannomas constitutes the most common morbidity associated with NF2. When the vestibular tumors are small, they can be resected completely with preservation of hearing; however, if the tumors are large, debulking is often all that is possible without damaging the facial nerve (CN VII) and CN VIII. Other tumors, such as meningiomas and ependymomas, cause symptoms from mass effect on the adjacent structures and are occasionally debulked or removed, although usually, serial MRIs are done for follow-up of these tumors.

Despite the large number of tumor types found in NF2, malignant transformation is rare and may be iatrogenic in many patients. In an international study by Baser et al, 5% of patients who received external-beam radiation developed malignant tumors at previously irradiated sites, whereas fewer than 1% of patients who did not receive radiation therapy developed malignancies.¹⁶ This suggests that the number of malignancies in the first group were radiation associated, similar to data regarding hereditary retinoblastoma. Fortunately, radiation therapy has a limited role in NF2 and is reserved for aggressive tumors and for patients who refuse surgical intervention.

• Mortality age is variable in patients with NF2, and many patients have relatively normal life spans. Age at diagnosis, the presence of intracranial meningiomas, and whether the patient was treated at a specialty center or not have been cited as the strongest predictors of mortality risk.¹⁷

Race

A racial predilection exists for NF2, although because the disease is autosomal dominant with a high penetrance, many patients have a strong family history.^{1, 14, 18}

Sex

Male and female patients are approximately equally affected because the disease is autosomal dominant.¹⁹

Age

Typically, the diagnosis of NF2 is made in the second or third decade of life, with a peak in the 20s. The diagnosis usually is made as a result of symptoms associated with CN VIII schwannomas. NF2 may be diagnosed earlier in children with a family history of the disease, as a result of early screening, or in those who initially present with diplopia or vision loss.

As a result of the high penetrance of NF2, patients with NF2 almost always present with this condition before age 60 years. Most are diagnosed before age 40 years.

Anatomy

CN VIII leaves the brainstem at the level of the mid pons and runs through the ambient cistern toward the internal auditory canal (IAC), adjacent to CN VII. Within the canal, CN VIII runs in the inferior portion, underneath the crista falciformis. Bill's bar, a thin layer of arachnoid tissue that can have a small osseous component, divides the upper portion of the canal into anterior and posterior segments, separating the upper portion of CN VIII (posterior) from CN VII (anterior). Whereas in sporadic cases a CN VIII schwannoma involves only CN VIII, in NF2, CN VII and the entire CN VIII are often encased by the tumor, making resection much more problematic.

Clinical Details

The clinical presentation of NF2 varies, but approximately 45% of patients are first diagnosed because of symptoms resulting from CN VIII schwannomas, such as hearing loss, tinnitus, balance impairment, and weakness in CN VII distribution. This is because CN VIII schwannomas are symptomatic at a relatively small size.

Meningiomas and other schwannomas are the next most common tumors to cause initial symptoms as a result of mass effect on the adjacent structures. Less frequently, skin tumors and visual loss are the initial findings, except when NF2 is diagnosed in the pediatric population.

In pediatric patients, ocular abnormalities are the most common reason to consider the diagnosis of NF2, although some children are diagnosed through screening when a family history is present. MacCollin and Mautner found that in 18 patients younger than 16 years, ocular abnormalities were the presenting symptom in 8 (44%), and only 1 patient (5.6%) presented with hearing loss.²⁰ Symptoms related to spinal tumors (eg, paraplegia, pain) and skin tumors each occurred in 4 patients (22%). Bosch et al found that although 78% of patients with adult-onset NF2 kept a visual acuity of 1 in both eyes, only 14% of patients with childhood onset did.⁹

Although children with CN VIII schwannomas may become symptomatic in their teens, most patients are not diagnosed until their third decade, with a mean age at diagnosis of 20 years. A proposed mild form of NF2, the Gardner form, has been described as occurring later in life as a result of a smaller tumor burden. The disease may also be exacerbated during pregnancy.

Preferred Examination

Screen for NF2 using contrast-enhanced MRI of the brain and entire spine.^{21, 22, 23} Contrast is important for detecting small schwannomas, particularly of the spinal nerve roots, as well as small intraparenchymal ependymomas.²⁴ Newer sequences, such as high-resolution fast spin-echo (FSE) T2 cisternography and true inversion recovery, can aid evaluation of the CNs.²⁵

Contrast-enhanced CT scan studies or gas CT cisternography, as well as myelography, have had limited roles since the emergence of MRI, but occasionally, they must be used in patients in whom MRI is contraindicated.²⁶

Limitations of Techniques

As a result of its excellent contrast and multiplanar capabilities, MRI optimally depicts the number, size, location, and extent of the central nervous system (CNS) neoplasms found in NF2. However, MRI does not detect most of the ocular abnormalities associated with the disease; these are evaluated best using funduscopy. In addition, cortical and choroid plexus calcifications may be missed on MRI, particularly when using FSE techniques. These are visualized better on CT scan studies.

Gas CT cisternography, in which injected intrathecal gas is maneuvered to outline CN VIII, is more sensitive than routine CT scan studies, but it is also invasive and less sensitive than MRI.

Myelography and CT myelography can depict spinal schwannomas well, but because they cannot be used to visualize intra-axial tumors, they are only indicated when patients cannot undergo MRI.

DIFFERENTIALS

Section 3 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT Scan
• MRI
• Angiography
• Intervention
• Multimedia
• References

Other Problems to Be Considered

• Other phakomatoses
• Cowden disease: Associated with multiple meningiomas, neurofibromas, and hamartomas, including Lhermitte-Duclos disease (cerebellar gangliocytoma), but not associated with CN VIII schwannomas
• Multiple meningiomatosis and meningioangiomatosis: Considered by some to be formes frustes of NF2; others consider them separate diseases
• Basal cell nevus syndrome (Gorlin syndrome): Associated with meningiomas, astrocytomas, and medulloblastomas but not associated with schwannomas

RADIOGRAPH

Section 4 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT Scan
• MRI
• Angiography
• Intervention
• Multimedia
• References

Findings

Intracranial abnormalities found in NF2 are not visible on plain radiographs, except in cases of hyperostosis from a meningioma. Widening of the neural foramina and scalloping of the posterior aspect of the vertebral bodies can be seen on plain radiographs of the spine and result from pressure erosion from the schwannomas rather than the dural ectasia that causes the bony malformations in NF1. Scoliosis is also associated with NF2 and can be measured most accurately on plain radiographs, although CT scan studies or MRI may be necessary to evaluate some of the more subtle spinal deformities.

Degree of Confidence

Foraminal widening and posterior vertebral scalloping is not specific for NF2. The dural ectasia of NF1, as well as some bone dysplasias, can cause scalloping of the posterior vertebral bodies similar to that seen in NF2; however, the scalloping in NF2 is a result of associated tumors. Although the scalloping from NF1 and NF2 are occasionally indistinguishable on plain radiographs, either MRI or CT scanning easily distinguishes between the 2.

NF2 is associated with scoliosis, but it is an uncommon cause of scoliosis, and no study has described scoliosis as a presenting sign of NF2.

CT SCAN

Section 5 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT Scan
• MRI
• Angiography
• Intervention
• Multimedia
• References

Findings

• CN VIII schwannomas are visualized on CT scans as strongly, but heterogeneously, enhancing cerebellopontine angle masses that extend from the IAC. On precontrast imaging, these schwannomas are isodense to hypodense with respect to brain tissue and may have associated cysts or hemorrhage. The pressure of the tumor often results in widening of the IAC and is best visualized using bone windows. Gas CT cisternography, with 0.5- to 1-mm slices, can demonstrate small tumors within the IAC that are typically missed on routine CT scanning. Small schwannomas of the other CNs are easily overlooked or not visualized because of their proximity to osseous structures and the relatively poor contrast resolution of CT scanning.
• Intracranial meningiomas present as enhancing extra-axial masses, often with internal calcifications and adjacent hyperostosis that are best visualized with bone windows. Adjacent white matter with decreased attenuation is commonly seen when tumors are large, likely representing edema. The persistence of this abnormality for years after the tumor has been resected suggests the likely existence of a demyelinating factor as well. When large enough, meningiomas may exhibit mass effect on the brain parenchyma and can be aggressive at times, invading the adjacent bone. Without contrast, meningiomas may have the same attenuation as the brain, but they typically have higher attenuation values resulting from the presence of calcium and a high nuclear-to-cytoplasmic ratio. Small tumors can be missed, particularly over the calvarium and in the posterior fossa, where beam-hardening artifact is the worst.
• Spinal schwannomas appear either as dumbbell-shaped enhancing masses extending out the neural foramina or as intradural extramedullary masses in the spinal canal. CT scans show widening of the foramina or pressure erosion on the adjacent vertebral body, and sagittal reformatted images are useful.
• Spinal meningiomas are found as intradural extramedullary masses, usually in the thoracic spine. They are best imaged on CT myelography, although they usually show enhancement on contrast CT scans. Occasionally, meningiomas extend into the neural foramina and appear as dumbbell-shaped masses with widening of the neural foramina. In these cases, distinguishing them from schwannomas or neurofibromas is difficult.
• Spinal ependymomas are intra-axial enhancing masses seen most frequently in the cervical cord and conus. When involving the conus or filum, an ependymoma may be pedunculated and appear as an extra-axial mass. Cervical cord ependymomas are well-marginated enhancing tumors that may exhibit associated cyst formation.

Degree of Confidence

Perform CT scanning only in patients with NF2 in whom MRI is contraindicated, because MRI provides superior tumor imaging and characterization. When CT scanning must be used, perform high-resolution techniques in the axial and coronal planes and consider CT cisternography for detecting small tumors. Even when visualized, the type of tumor is often difficult to identify on CT scans, because a large amount of overlap is seen in tumor appearance. CT myelography is adequate in depicting the extra-axial lesions of NF2, but it is relatively poor at detecting ependymomas. CT scanning with 3-dimensional (3-D) volumetric rendering can be useful for preoperative planning in patients with NF2 and associated scoliosis or spinal dystrophy.

MRI

Section 6 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT Scan
• MRI
• Angiography
• Intervention
• Multimedia
• References

Findings

CN VIII schwannomas are well-defined masses arising from the IAC and frequently extend into the cerebellopontine angle, demonstrating an ice cream cone or mushroom shape (see Image 1).

• CN VIII schwannomas often have heterogeneous signals, but they are typically isointense to hypointense on T1-weighted images and hyperintense on T2-weighted images.
• High-resolution, heavily T2-weighted sequences have been used to detect small CN VIII schwannomas and appear to be approximately as sensitive as contrast MRI.
• Using this technique, the bright cerebrospinal fluid (CSF) around CN VII and CN VIII is used as a contrast agent, and schwannomas appear as small rounded masses that efface the CSF in the canal.
• This technique is also useful in detecting cochlear involvement by the tumor, because the cochlear turns can normally be easily identified as curvilinear areas of increased signal.

Following contrast administration, CN VIII schwannomas enhance avidly but often heterogeneously, particularly in larger tumors.

Nonenhancing areas of necrosis are often present as the schwannomas enlarge, and associated cysts or blood products from internal hemorrhage may be present.

Other CN schwannomas have a similar MRI appearance and differ only in location, occurring along the paths of the other CNs. The multiplanar capability of MRI is particularly useful in distinguishing a CN schwannoma from a meningioma adjacent to a nerve.

Meningiomas in NF2 have the same distribution and signal characteristics as spontaneous meningiomas, occurring most frequently along the falx and over the convexities (see Image 2).

• Meningiomas are extra-axial tumors and thus demonstrate cortical buckling and a CSF cleft.
• A confluent area of white matter with increased T1 signal and decreased T2 signal may be seen in the adjacent brain parenchyma and likely results from a combination of vasogenic edema and demyelination.
• Meningiomas typically are isointense with gray matter on all sequences and, when small, can be difficult to detect without contrast.
• Signal intensity can vary, and almost any combination of T1 and T2 signals can be seen.
• Cyst formation is uncommon, but calcification occurs frequently and can cause the tumor to appear heterogeneous.
• Following gadolinium administration, intense and generally homogeneous enhancement is seen, and a dural tail of enhancing dural tissue is often found extending from the tumor's dural attachment, although this is not specific for meningioma.^{27, 28}
• Meningiomas in patients with NF2 may be more aggressive than spontaneously occurring ones, and the tumor may invade the adjacent calvarium and extend into the paranasal sinuses (see Image 3).

Spinal meningiomas are also associated with NF2 and are often multiple in number. Unlike intracranial meningiomas, the spinal type calcifies in fewer than 10% of patients (see Image 4).

• Spinal meningiomas are typically intradural and extra-axial but can present as dumbbell-shaped masses extending through the neural foramina. In this situation, distinction from a neurofibroma or schwannoma is difficult, although the schwannoma should be brighter on T2-weighted images.
• Meningiomas are usually isointense relative to the spinal cord on all image sequences and enhance strongly following gadolinium administration.
• Although most spinal meningiomas have a broad dural attachment similar to their intracranial counterparts, dural tail signs are found less frequently in spinal meningiomas.

Spinal ependymomas found in NF2 are divided into 2 groups: those that occur in the upper cord and those that occur in the conus.

• Cord tumors are well-marginated, intensely enhancing lesions, frequently associated with cyst formation and hemorrhage. Ependymomas may be isointense or hypointense relative to the spinal cord on T1-weighted images and are always bright on T2-weighted images, although a peripheral rim of decreased T2 signal has been proposed as being suggestive of ependymoma.
• Conus ependymomas are more often large tumors that can fill the entire spinal canal with heterogeneous signal and enhancement. When small, the tumors may be well-marginated intra-axial lesions, but when larger, they may appear to arise from the extra-axial space.

Multiple extradural masses extending through the neural foramina are found in both NF1 and NF2, although in NF2 (unlike in NF1), these tumors are usually schwannomas. The tumors often have both an intraspinal and an extraspinal component, demonstrate a classic dumbbell shape, and are typically multilevel and bilateral. Signal intensities for spinal schwannomas are the same as those for intracranial schwannomas, and strong contrast enhancement is seen. Because of the multifocality of the spinal schwannomas and an association with scoliosis, coronal MRI often is helpful.

Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have recently been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Fibrosing Dermopathy. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans.

As of late December 2006, the FDA had received reports of 90 such cases. Worldwide, over 200 cases have been reported, according to the FDA. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. For more information, see the FDA Public Health Advisory or Medscape.

Degree of Confidence

MRI is the imaging modality of choice in NF2 and is accurate in detecting even small tumors. Separation of intracranial schwannomas from meningiomas may be difficult at times but is usually of little clinical value. The evaluation of the extent, size, and number of intracranial tumors in NF2 is accomplished best by MRI because of its multiplanar capability, its contrast resolution, and the spectrum of pulse sequences, each of which adds different information.

Spinal schwannomas, meningiomas, and ependymomas are also visualized best on MRI. Usually, no other imaging modality is necessary either at the time of diagnosis or as part of a follow-up regimen. Although MRI can image osseous vertebral abnormalities associated with NF2, CT scanning visualizes them better.

ANGIOGRAPHY

Section 7 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT Scan
• MRI
• Angiography
• Intervention
• Multimedia
• References

Findings

Angiography is of limited use in NF2 because most tumors are not visualized. An exception is the "mother-in-law sign" ("arrives early and stays late") of meningioma contrast enhancement. This sign comes from recognition of meningiomas during angiography by their early contrast enhancement and delayed washout. The early contrast enhancement is caused by the enlarged feeding vessels, usually pial or meningeal arteries, and the delayed tumor staining is from lack of capillary blood-brain barriers within the tumor. Unfortunately, like many signs in radiology, this is not specific and can be seen in other hypervascular tumors.

Because ependymomas and schwannomas are not particularly vascular, they are often not visible on angiography; however, when large enough, secondary mass effect on the adjacent brain can be recognized.

INTERVENTION

Section 8 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT Scan
• MRI
• Angiography
• Intervention
• Multimedia
• References

Radiologic intervention plays a limited role in patients with NF2. In large meningiomas, intravascular embolization can be performed to shrink the tumor before further treatment, although this has not been described specifically in patients with NF2.

Medical/Legal Pitfalls

• Failure to make a timely diagnosis of NF2. A CN schwannoma, including a unilateral CN VIII schwannoma or meningioma in a younger patient, suggests the possibility of NF2, which should result in genetic testing and a full MRI of the brain and spine.
• Older patients with meningiomas or a unilateral CN VIII schwannoma should not undergo an expensive workup for NF2 because the disease usually presents before the age of 40 years. Patients older than 60 years with bilateral IAC masses are unlikely to have NF2 if it has not been diagnosed previously. A few reports of bilateral IAC metastases exist.

Related Medscape topics:
Resource Center Genomic Medicine
Resource Center Medical Malpractice and Legal Issues

Special Concerns

• NF2 is an autosomal dominant condition. Because NF2 is almost always diagnosed during the reproductive years, patients and their families should receive extensive genetic counseling following diagnosis, and their children should be screened early in life.

Related Medscape topic:
Resource Center Genomic Medicine

MULTIMEDIA

Section 9 of 10  

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT Scan
• MRI
• Angiography
• Intervention
• Multimedia
• References

Media file 1:  Axial T1-weighted postcontrast image demonstrates bilateral internal auditory canal-enhancing masses that are diagnostic for neurofibromatosis type 2 (NF2). No biopsy is necessary for the diagnosis. Notice the en plaque meningioma anterior to the brainstem.
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Media type:  MRI

Media file 2:  Sagittal T1-weighted postcontrast image in a patient with known neurofibromatosis type 2 that demonstrates 2 midline meningiomas (arrowheads), one over the convexity and one along the vein of Galen. The enhancing mass in the medulla (arrow) most likely is an ependymoma.
	View Full Size Image
Media type:  MRI

Media file 3:  Axial postcontrast T1-weighted image demonstrates a large enhancing sellar meningioma surrounding both internal carotid arteries in this case of neurofibromatosis type 2 (NF2) (black arrows). Enhancing tissue in the ethmoid air cells also represents a meningioma extending through the cribriform plate. Meningiomas in patients with NF2 can be more aggressive and invasive than spontaneous meningiomas. Note the small, round, enhancing extra-axial mass posterior to the tectum (white arrow). Although this could represent another meningioma, the shape and location suggest it is a trochlear (CN IV) schwannoma instead.
	View Full Size Image
Media type:  MRI

Media file 4:  Sagittal T1-weighted postcontrast image of the thoracic spine demonstrates an enhancing extra-axial meningioma (arrow) anterior to the cord with a complex enhancing mass (arrowheads) that represents a conus ependymoma filling the spinal canal in the lower thoracic spine.
	View Full Size Image
Media type:  MRI

Media file 5:  Magnetic resonance image (MRI) in a 62-year-old man who presented with unilateral hearing loss. This MRI demonstrates an enhancing mass in the right internal auditory canal (IAC) that was interpreted as a probable cranial nerve VIII (CN VIII) schwannoma. Although no other abnormalities were detected, the examination was performed as a limited MRI and imaged only the internal IACs. Further screening was not indicated because the chance that this patient had NF2 is exceedingly low.
	View Full Size Image
Media type:  MRI

REFERENCES

Section 10 of 10

• Authors and Editors
• Introduction
• Differentials
• Radiograph
• CT Scan
• MRI
• Angiography
• Intervention
• Multimedia
• References

1. Baser ME, R Evans DG, Gutmann DH. Neurofibromatosis 2. Curr Opin Neurol. Feb 2003;16(1):27-33. [Medline].
2. Bance M, Ramsden RT. Management of neurofibromatosis type 2. Ear Nose Throat J. Feb 1999;78(2):91-4, 96. [Medline].
3. Evans DG. Neurofibromatosis type 2: genetic and clinical features. Ear Nose Throat J. Feb 1999;78(2):97-100. [Medline].
4. Jacoby LB, MacCollin M, Parry DM, et al. Allelic expression of the NF2 gene in neurofibromatosis 2 and schwannomatosis. Neurogenetics. Apr 1999;2(2):101-8. [Medline].
5. Fontaine B, Sanson M, Delattre O, et al. Parental origin of chromosome 22 loss in sporadic and NF2 neuromas. Genomics. May 1991;10(1):280-3. [Medline].
6. Fontaine B, Hanson MP, VonSattel JP, et al. Loss of chromosome 22 alleles in human sporadic spinal schwannomas. Ann Neurol. Feb 1991;29(2):183-6. [Medline].
7. National Institutes of Health. Consensus Development Conference. Neurofibromatosis Conference Statement. Arch Neurol. 1988;45 (5):575-8. [Medline].
8. Gutmann DH, Aylsworth A, Carey JC, et al. The diagnostic evaluation and multidisciplinary management of neurofibromatosis 1 and neurofibromatosis 2. JAMA. Jul 2 1997;278(1):51-7. [Medline].
9. Bosch MM, Boltshauser E, Harpes P, Landau K. Ophthalmologic findings and long-term course in patients with neurofibromatosis type 2. Am J Ophthalmol. Jun 2006;141(6):1068-77. [Medline].
10. Landau K, Yasargil GM. Ocular fundus in neurofibromatosis type 2. Br J Ophthalmol. Oct 1993;77(10):646-9. [Medline].
11. Kaye LD, Rothner AD, Beauchamp GR, et al. Ocular findings associated with neurofibromatosis type II. Ophthalmology. Sep 1992;99(9):1424-9. [Medline].
12. Landau K, Dossetor FM, Hoyt WF, Muci-Mendoza R. Retinal hamartoma in neurofibromatosis 2. Arch Ophthalmol. Mar 1990;108(3):328-9. [Medline].
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Article Last Updated: Mar 17, 2008