Lisch nodules of the iris in neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is a common autosomal dominant disease. The Lisch nodule represents one of the most common NF1 ocular manifestations. Several studies have reported that the Lisch nodule is a melanocytic hamartoma but its pathogenesis is still debated. We have studied the histopathological and ultrastructural features of a Lisch nodule of a 50-year-old woman biopsied during an intracapsular cataract extraction. Our researches revealed that it was composed of three main cytotypes: pigmented cells, fibroblast-like cells and mast cells, showing a pattern similar to a neurofibroma. Furthermore, we hypothesize that Lisch nodules are compatible with neurofibromas.