Von Recklinghausen's neurofibromatosis, also known as NF1, is an inherited neuroectodermal abnormality characterized by the appearance of six or more cafe-au-lait lesions, axillary freckles (Crow's sign) multiple neurofibromas, and pigmented hamartomas of the iris (Lisch nodules). This is inherited as an autosomal dominant trait. The gene for NF1 is located on chromosome 17. NF1 is relatively commonly seen as a new mutation. Characteristically, cafe-au-lait lesions are seen at birth. In adults these lesions usually are greater than 1.5 cm in length. Freckles can also be present in the axillae. Axillary freckling is very uncommon except in neurofibromatosis. Axillary freckling usually is noted later than the appearance of cafe-au-lait lesions. Neurofibromas appear in adolescence or early adulthood. Plexiform neuromas and schwannomas are neural tumors occurring along the course of a nerve. The Lisch nodules characteristic of the disease are evident in the iris on slit lamp examination, usually by the teens.
The extent of skin involvement does not reliably indicate the extent of central nervous system involvement. Optic nerve gliomas, as well as other intracranial tumors can occur. Sarcomatous change in any lesion is uncommon before age forty.
- Treatment is symptomatic. Neurofibromas have been treated successfully with carbon dioxide laser ablation.
- Genetic counseling is recommended.
- Ketotiphen orally has been reported to reduce skin itch.