Multiple cranial nerve schwannomas with multifocal cystic meningomatosis in a case of neurofibromatosis type 2

Multiple cranial nerve schwannomas with multifocal cystic meningomatosis in a case of neurofibromatosis type 2

European Journal of Radiology Extra 75 (2010) e87–e91 Contents lists available at ScienceDirect European Journal of Radiology Extra journal homepage...

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European Journal of Radiology Extra 75 (2010) e87–e91

Contents lists available at ScienceDirect

European Journal of Radiology Extra journal homepage: intl.elsevierhealth.com/journals/ejrex

Multiple cranial nerve schwannomas with multifocal cystic meningomatosis in a case of neurofibromatosis type 2 Samta Parteki a , Monali Raval a,∗ , Rima Kumari a , Surina Singhal a , Nitij Gupta b a b

Neuroradiology, Institute of Human Behaviour and Allied Sciences (IHBAS), Jhilmil, Dilshad Garden, Delhi 110095, India Focus Imaging Centre, IHBAS Campus, Delhi, India

a r t i c l e

i n f o

Article history: Received 22 January 2010 Received in revised form 22 June 2010 Accepted 22 June 2010

Keywords: Neurofibromatosis Schwannoma 3D FIESTA Cystic meningomatosis Ependymoma

a b s t r a c t Type 2 neurofibromatosis is an autosomal dominant disease characterized by the development of bilateral vestibular schwannomas. We are presenting a rare case of NF2 with multiple cranial nerve schwannomas involving the 3rd, 4th, 5th, 7th, 8th, 9th, 10th and 11th cranial nerves with multifocal cystic meningiomatosis and fourth ventricle ependymoma these findings were better depicted on high field MR using 3D FIESTA which has obviated the need of contrast MRI in this particular case. © 2010 Elsevier Ireland Ltd. All rights reserved.

1. Introduction Neurofibromatosis type 2 (previously called bilateral acoustic neurofibromatosis or central neurofibromatosis and abbreviated as NF 2 or BAN) affects about 1 in 25,000 people without regard to sex and race. Although it shares a name with neurofibromatosis type 1 (NF1; von Recklinghausen disease), the two 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 schwnnomas, meningiomas and ependymomas. We are presenting a rare case of NF2 with multiple cranial nerve schwannomas and multifocal cystic meningiomatosis with fourth ventricle ependymoma. To the best of our knowledge, MR findings of such a case have not been previously reported in the literature. 2. Case report A 16-year-old male presented with gradual onset of external otalgia, slight dysphagia, tinnitus and deafness for the past 2 years. On general physical examination the patent had multiple subcutaneous nodules. Otoscopic examination was normal and

∗ Corresponding author. Tel.: +91 9868396851. E-mail addresses: [email protected] (S. Parteki), [email protected] (M. Raval), [email protected] (R. Kumari), [email protected] (S. Singhal), [email protected] (N. Gupta). 1571-4675/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrex.2010.06.009

audiometric test revealed bilateral sensorineural deafness. Ophthalmological examination revealed left hyper-mature cataract. With this spectrum of symptoms and clinical picture, a tentative impression of NF 2 was made and neuroimaging was advised. Conventional MR imaging was performed on a 3 T MR scanner (GE Signa HDX) and additional 3D FIESTA sequence was done for high resolution imaging of the cranial nerves. 3D FIESTA images revealed multiple extraaxial lobulated masses along the course of bilateral 3rd, 4th, 5th, 7th, 8th, 9th, 10th and 11th cranial nerves. Symmetrical lobulated lesions were seen arising from 3rd and 4th cranial nerves indenting the prechiasmtic optic nerve and optic chiasma (Fig. 1a and b). Masses were seen along the course of both trigeminal nerves involving their cisternal segments and extending into bilateral Meckles cave and cavernous sinuses (Fig. 2a and b). Symmetrical lesions were also seen causing widening of both internal auditory canals with intraand extracanalicular 7–8th nerve involvement (Fig. 3a–c). Lobulated masses were also seen along the course of 9th, 10th and 11th nerves in the jugular foramen (Fig. 4a and b). The lesions were showing relatively homogenous signal characteristics, appearing isointense to gray matter on both T1 and T2/FLAIR images. No significant intralesional hemorrhage or necrosis seen in any of these masses. In addition to these findings, multiple small corticosulcal/subpial CSF isointense cystic foci were seen along both the cerebral and cerebellar hemispheres causing scalloping of the underlying brain parenchyma. No significant perilesional edema or intralesional restriction of diffusion was seen (Fig. 5).

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Fig. 1. (a) Axial 3D FIESTA image at the level of optic chiasma showing lobulated mass arising from 3rd and 4th nerves indenting the prechiasmatic optic nerve and optic chisma. (b) Coronal T2 image at the level of cavernous sinus showing lobulated mass arising from 3rd and 4th nerves.

Another large lobulated hetrogenous mass with solid cystic and hemorrhagic components was seen in the inferior recess of fourth ventricle. These findings suggested the possibility of multiple cranial nerve schwannomas with multifocal cystic meningomatosis and fourth ventricle ependymoma. 3. Discussion Neurofibromatosis type 2 is an autosomal dominant syndrome first described by Wishart in 1822,the disease was not separated from von Recklinghausen disease until 1987,when it was proven that the two disorders arose from different chromosomes. The genetic defect responsible for NF2 is a mutation of 22q12 the same chromosomal abnormality found in spontaneous spinal schwannoma indicating that a single location causes schwann cell tumor growth [1,2]. In 1988,the National Institute of health had led following criteria for the diagnosis for NF2 [3], bilateral vestibular schwannomas or the family history of NF2 plus either a eight nerve

Fig. 2. (a and b) Axial 3D FIESTA and coronal T2 image at the level of pons showing bilateral trigeminal nerve masses within prepontine cisterns and obliterating both Meckel’s caves. Cystic meningiomatosis seen in both temporal lobes scalloping underlying parenchyma.

mass and/or the following; schwannoma, neurofibroma, glioma, meningioma or juvenile sublenticular opacity. Cutaneous markers are rarer in NF2 as compared to NF1, CNS lesions are seen in virtually all the cases and include non-neoplastic intracranial calcification and spinal cord nerve root tumor [3]. In the past 2 decades, a revision of these diagnostic criteria was proposed with the addition of the presumptive or probable diagnosis of NF2. These are as follows: • Definite diagnosis of NF2 -Bilateral CN VIII schwannoma on MRI or CT scan (no biopsy needed). -First degree relative with NF2 and either unilateral early onset CN VIII schwannoma (age < 30 years) or any of the following: Meningioma Glioma Schwannoma

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Fig. 4. (a and b) Axial 3D FIESTA and coronal T2 image images at the level of jugular foraminae showing isointense mass within the left cerebellomedullary cistern and right jugular foramen. Subpial cystic lesions seen in both cerebellar hemispheres.

Fig. 3. (a–c) Axial 3D FIESTA and coronal T2 image images at the level of internal auditory canals showing lobulated masses along bilateral 7–8th nerve complexes with intra and extracanalicular extension (icecream cone appearance).

Juvenile posterior sub capsular lenticular opacity (juvenile cortical cataract) • Presumptive diagnosis of NF2 -Early onset of unilateral of unilateral CN VIII schwannoma on MRI or CT scan detected in younger than 30 years and one of the following: Meningioma Glioma Schwannoma Juvenile posterior sub capsular lenticular opacity (juvenile cortical cataract) -Multiple meningiomas (>2) and unilateral CNVIII schwannoma or one of the following: Glioma Schwannoma Juvenile posterior sub capsular lenticular opacity (juvenile cortical cataract)

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Fig. 5. Midsagittal T2W image revealing inferior fourth ventricular ependymoma and cystic meningiomatosis scalloping superior cerebellar surface.

Baser et al. studied [4] the different sets of diagnostic criteria and concluded that none of them is adequate in the diagnosing patient who does not have bilateral acoustic neuromas at the initial work up the authors proposed that a single set of the diagnostic criteria should be devised to supplant the 4 existing sets. Intracranial schwannomas of the VIII cranial nerve complex are the hallmark of NF2. These typically arise from the vestibular nerve; the trigeminal nerve is next most frequently affected cranial nerve. Presence of occulomotor, trochlear or abducent nerve tumors should raise the possibility of NF2. Similarly, involvement of more than one cranial nerve should warrant a work up for NF2 [5,6]. Schwannomas arise from Schwann cells which support and protect nerve cells and provide nerves with the insulation they need to conduct information. J Antinhemo and R. Sankila have estimated the incidence of multiple schwannomatosis as 3% in the NF2 patient population [7,8]. These tumors are well-demarcated solid masses that are isoto hypointense on T1- and T2-weighted images with homogenous contrast enhancement. High field MR imaging with additional newer sequences, such as 3D FIESTA (Fast Imaging Employing Steady State Accquisition) which is a high resolution, heavily T2-weighted sequence 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. Nonenhancing areas of necrosis are often present as the schwannomas enlarge, and associated cysts or blood products from internal hemorrhage may be present [9,10]. Our patient is a rare case in which MR identified schwannomas of almost all the cranial nerves best depicted on the 3D FIESTA sequence. Intracranial meningiomas found in NF2 are usually multiple and appear as well circumscribed intensely enhancing extra axial dural based masses.

Meningomatosis is a rare, benign hamartomatous lesion. It was first described by Bossoe and Nuzum in 1915; it was named by Worster-Drought et al. in 1937, it is found in the cerebral cortex and leptomeninges and known to be associated with NF2 in nearly 50% reported cases [11], in most of the reported cases, the lesions are solitary, although multiple lesions have occasionally been described, approximately 1% of patients with NF2 have multiple meningomatosis. Our patient is among the few reported cases having multifocal cystic meningomatosis which was well depicted on conventional as well as high resolution 3D FIESTA sequence [12,13]. Ependymomas are the most common intraparenchymal tumor in NF2, although gliomas are rarely associated with the syndrome and schwannomas rarely present as solely intraparenchymal lesion. Our patient had a typical ependymoma within the fourth ventricle. Multiple studies have described benign intracranial calcifications, particularly in the choroid plexus, cerebellar hemispheres and cerebral cortex, in association with NF2. Spinal tumors seen in NF2 include schwannoma, meningioma, and ependymoma. Schwannomas may present as intradural extramedullary masses or may involving exiting nerve roots. Nerve root tumor in NF2 may present as dumbbell shaped lesion exiting through the neural foramina, similar to neurofibromas of NF1, but histology reveals that most of these are schwannomas. Meningiomas present as intramedullary masses that are similar to spontaneous meningioma and typically involving the thoracic spine; they are often multiple in number. Most intramedullary spinal tumors inNF2 are ependymomas and arise in either the upper cervical cord or the conus [14,15]. Osseous abnormalities seen in NF2 are usually secondary to spinal tumors. A few ocular abnormalities occur in NF2, including a form of early onset cataract termed juvenile posterior subcapsular lenticular opacity, patient can also have hamartomas of retina and choroids and the patient’s vision may be affected by optic nerve (CNII) sheath meningiomas [16]. Ours is a rare case of NF2 with schwannomas arising from almost all the cranial nerves bilaterally in addition to the findings of multifocal cystic meningiomatosis and ependymoma. These findings were well depicted on high field MR imaging using 3D FIESTA. Conflicts of interest There is no conflict of interest among the authors or the author’s institutions. References [1] Evans DG. Neurofibromatosis type 2: genetic and clinical features. Ear Nose Throat J 1999;78(February (2)):97–100. [2] Jacoby LB, MacCollin M, Parry DM, et al. Allelic expression of the NF2 gene in neurofibromatosis 2 and schwannomatosis. Neurogenetics 1999;2(April (2)):101–8. [3] National Institutes of Health. Consensus development conference. Neurofibromatosis conference statement. Arch Neurol 1988;45(5):575–8. [4] Baser ME, R Evans DG, Gutmann DH. Neurofibromatosis 2. Curr Opin Neurol 2003;16(February (1)):27–33. [5] Barkovich J, Nishimura K, Kjos B, et al. Neurofibromatosis type 1 and 2: cranial MR findings. Radiology 1989;172:527. [6] Antinheimo J, Sankila R, Carpan O, Pukkala E, Soinio M. Neurology 2000;54:71. [7] Osborn Anne G. Disorders of histogenesis: neurocutaneous syndromes, diagnostic neuroradiology. Mosby: Year Book; 1994 p. 84–93. [8] Atlas Scott W. CNS manifestations of the phakomatoses and other inherited syndromes: MRI of the brain and spine. 2nd ed. Lipincott Raven; 1996 p. 781–786. [9] Gillespie JE. Imaging in neurofibromatosis type 2: screening using magnetic resonance imaging. Ear Nose Throat J 1999;78(February (2)). p. 102–103, 106, 108–109. [10] Mautner VF, Tatagiba M, Lindenau M, et al. Spinal tumors in patients with neurofibromatosis type 2: MR imaging study of frequency, multiplicity, and variety. AJR Am J Roentgenol 1995;165(October (4)):951–5.

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