Sir,

Atypical manifestation of neurofibromatosis type 2 (NF2) in a 10-year-old boy was recently reported in Eye.1 I would like to present another 10-year-old child with the atypical presentation of Horner syndrome. Although a diagnosis of NF2 is most often made in adults, both cases highlight that onset is also possible in childhood. Further, eye manifestations may be the presenting symptoms.

Case report

Seven years ago, a 10-year-old girl was referred for ophthalmic opinion as part of a general investigation because of heredity of NF2 in her father and half-brother. At that time there was no multidisciplinary follow-up program of relatives of NF2 patients in our hospital and her eyes had not previously been examined. Audiology examination had not revealed any vestibular schwannomas. She had no eye complains. Visual acuity was normal (6/6) both eyes. The anterior segment was normal in her right eye, but there was a posterior subcapsular opacity in her left eye, not affecting the visual acuity. No Lisch noduli were found. Horner's syndrome was noted in the left eye with a moderate ptosis and an anisocoria, most prominent in dark. Both fundi were normal. She had no strabismus.

The girl was investigated by the paediatric neurologists, and a magnetic resonance imaging (MRI) scan revealed an intraspinal/thoracic tumour with an extension from CVI to ThII and extrapleurally left side (Figure 1). The tumour was operated in two sessions when she was 11 years old. Histological examination showed neurofibroma. Minor vestibular schwannomas were detected at 15 years of age and are followed up, but still not operated at the age of 17 years.

Figure 1
figure 1

Thoracic MRI showing an intraspinal/thoracic tumour with an extension from CVI to ThII and extrapleurally left side (with permission of the patient).

Full size image

The girl is followed up regularly by audiologist, paediatric neurologist, and ophthalmologist. Her posterior subcapsular cataract remains similar and she still has a normal visual acuity in both eyes.

NF2 is an autosomal, dominantly inherited disease and is associated with mutations in the NF2-gene, localized to chromosome 22.2 It is characterized by bilateral vestibular schwannomas, that is, ‘acoustic neuromas’. Other central nervous tumours may also occur, such as meningeomas of the brain, schwannomas of other cranial nerves, spinal nerve roots, and peripheral nerves and gliomas.3, 4

Various eye manifestations are described in patients with NF2, the most common being cataracts that are described in up to 80%.5, 6 Cataracts often have an early onset and may even be congenital.3 Other ophthalmologic manifestations include retinal hamartomas and epiretinal membranes, choroidal hamartomas, optic meningeomas and gliomas, conjunctival neurofibromas, eye muscle pareses, and strabismus.3, 5, 6, 7 Reduced corneal sensibility owing to fifth nerve lesions and corneal opacities owing to facial nerve palsy may also occur. Lisch noduli are, however, rare.

Comment

A case of Horner syndrome in a patient with NF1 was previously reported in Eye.8 To my knowledge, however, this patient is the first reported case of NF2 presenting with Horner syndrome. As spinal tumours are frequent in NF2, this is an ophthalmologic manifestation that ought to be kept in mind.

Patients with NF2 are most often diagnosed as adults, but 10% have their onset before 10 years.3 NF2 must therefore be considered as a differential diagnosis also in children. In 13% of patients with NF2, eye manifestations were the presenting symptom.9 This underlines the importance of including ophthalmologic examination in multidisciplinary screening programs of first-degree relatives of patients with NF2 as well as in follow-up of patients with established NF2. Eye examinations are particularly important for early diagnosis, which may contribute to a better outcome after surgery for vestibular schwannomas. Further, early detection and treatment of eye manifestations may also lead to prevention of amblyopia.