A Complete Constellation of Nervous System Lesions of NF2: Imaging Evaluation

The radiological findings fulfilling the criteria of neurofibromatosis type 2 (NF2) were reviewed. NF2 is a rare disease with few cutaneous but frequent, typical radiological findings in the central nervous system. The presenting symptom is most commonly hearing loss due to acoustic schwannomas, although symptoms emanating from other intracranial or tumors are not uncommon. The discovery of multiple spinal neurofibromas or multiple meningiomas without cutaneous lesions should initiate a search for acoustic schwannomas even when the patient has normal hearing as in our case patient who actually presented for weakness of all four limbs.


Introduction
Neurofibromatosis (NF) is an inherited autosomal dominant disease mainly affecting the skin, nervous and musculoskeletal system, first described by Von Recklinghausen in 1882. Recently, NF has been divided into two types, defined according to the location of their genetic defect. In NF1, the defect is on chromosome 17, and in NF2, on chromosome 22. NF2 diagnosis might be difficult for the clinician because cutaneous manifestations are often sparse or missing. It is therefore not unusual for the diagnosis to be made by the radiologist. The aim of the present paper is to assess the radiological findings in a patient who fulfilled all the CNS lesions criteria of NF2.

Case History
An 18-year-old male presented with a history weakness in all four limbs more in upper limbs and chronic headache. Family history was positive for similar complaints and early death of his elder brother. General physical examination revealed an alert and oriented patient, with normal cognitive function, with right lower cervical and left upper thoracic swellings. He had bilateral moderate hearing loss and reduced power in all four limbs. Few scattered skin lesions that resembled skin tags were also found. Imaging evaluation of spine was done, revealed multiple spinal and extraspinal neurofibromas and few intramedullary lesions. Later cranial MR was done, revealed bilateral intracanalicular acoustic schwannomas with two en plaque meningiomas in right frontoparietal region. Considering the CNS lesions and positive family history, a diagnosis of NF2 was done (Figures 1, 2, 3, 4, 5, and 6).

Discussion
The term MISME has been proposed to the NF2 syndrome, due to multiple inherited schwannomas (MIS), meningiomas (M), and ependymomas (E). In addition to the neoplasms, posterior subcapsular lenticular opacity (juvenile cortical cataract) is often present. Patients with NF2 may have cutaneous schwannomas that resemble skin tags, but they rarely have caféau lait spots and do not demonstrate the cutaneous neurofibromas like NF1. In 1997, Gutmann et al. proposed revised criteria for diagnostic of the syndrome [1] ( Table 1).
The findings of multiple spinal neurofibromas without cutaneous lesions should arise the suspicion of NF2, and examination should be done to rule out acoustic schwannomas even if the hearing is normal. Multiple intracranial 2 Case Reports in Radiology Table 1: Gutmann et al. [1].
In the search for acoustic tumours, MRI with intravenous contrast medium should be used, as its sensitivity is higher than that of other modality [2]. Several authors have studied series of cases to try to define incidence of the tumors in cases of NF2. Mautner et al. studied 48 patients with NF2, in which the prevalence of findings were vestibular

Conclusion
Neurofibromatosis type 2 (NF2) is a rare autosomal dominant disorder with an incidence of 1:37,000 [5]. Its hallmark is the presence of bilateral vestibular schwannomas. Additional manifestations include spinal tumours as well as brain tumours, peripheral nerve tumours, and cataracts [2]. The detection of multiple asymptomatic spinal lesions in patients with a symptomatic spinal tumour led to the assumption that  spinal tumours are more common in patients with NF2 than has been assumed [4]. Confirmation of a high frequency of spinal tumours would show that such tumours are criterion of the disease and aid in the diagnosis in family members and sporadic cases with suggested NF2.