RESUMEN
INTRODUCTION: Von Recklinghausen's neurofibromatosis is an autosomal dominant disorder that affects both sexes at the same rate. The diagnosis is suggested by the family history, the presence of multiple neurofibromas and cutaneous pigmentary macules but is only confirmed by the presence of the Lisch nodules at the iris level and by histological exam. The disease is associated with different nervous system, bone, endocrine, blood vascular abnormalities. PURPOSE: Evaluation of Lisch nodules in patients with Recklinghausen disease or immediate relatives, that do not present characteristic cutaneous lesions. MATERIAL AND METHOD: The study involves three cases of Recklinghausen neurofibromatosis and also a part of their immediate relatives. The diagnosis of NF1 was based on clinical aspects, family pedigree analysis and ophthalmological exam. The histological exam was only performed for complicated cutaneous lesions. RESULTS AND DISCUSSIONS: The clinical exam revealed characteristic cutaneous lesions but also Lisch nodules in all three studied cases. According to the pedigrees, Recklinghausen disease is inherited as an autosomal dominant trait (in 2 patients), but it may also arise as de novo mutations (1 patient). The ophthalmological exam performed for the patients' relatives, identified Lisch nodules in all subjects presenting cutaneous lesions (neurofibromas), and also in children without characteristic cutaneous features. Both pedigree analysis and ophthalmological examination are compulsory, noninvasive methods for precocious diagnosis of the disease and the identification of high-risk patients. CONCLUSIONS: Lisch nodules are ophthalmological and pathognomonic markers of Recklinghausen neurofibromatosis. Lisch nodules facilitate a precocious, noninvasive diagnosis inclusively in children without cutaneous features (neurofibromas) but positive antecedents. Ophthalmological examination and pedigree analysis are compulsory both in patients and their immediate relatives.