[Lisch nodules: an ophthalmic marker of neurofibromatosis type 1]

Von Recklinghausen disease or neurofibromatosis type I (NF1) is the most common phacomatosis. It is inherited in an autosomal dominant manner. Lisch nodules are the most common ophthalmic manifestation of NF1. They are reported in 73-95% of cases. We here report the case of a 49-year-old female patient referred for a consultation with an ophthalmologist for routine eye check-up after the onset of the following symptoms: coffee-with-milk colored spots and multiple neurofibromas (A). She reported similar family history. Visual acuity was 10/10 P2 in both eyes. Examination of the anterior segment showed several Lisch nodules in both irises. They were scattered over the entire iris surface and varied in size (B). Fundus examination was unremarkable. CT scan of the brain and the orbit as well as thoracoabdominal CT scan showed no associated lesion. The patient met NIH diagnostic criteria for NF1. Lisch nodules are small brown dome-shaped lesions developing on the surface of the iris, with well-defined edges, embedded in the stroma and lighter than iris pigmentation. Differential diagnosis includes iris mammillations, iris naevi, iris melanoma, iris granulomatous nodules. Unlike skin signs, the presence of multiple Lisch nodules are considered a specific indication of NF1. These nodules may occur in childhood and their prevalence and number increase with age. Thus, periodic eye examinations in subjects with suspected neurofibromatosis type I may help to improve early diagnosis.