Neurofibromatosis true all, except-

Neurofibromas and von Recklinghausen's Disease Neurofibromas may occur as a solitary, fusiform cutaneous tumor of a single nerve, but more often are multiple associated with von Recklinghausen's disease. Solitary neurofibroma is a tumor of adults but multiple neurofibromas or neurofibromatosis is a hereditary disorder with autosomal dominant inheritance. Solitary neurofibroma is generally asymptomatic but patients with von Recklinghausen's disease have a triad of features: 1.Multiple cutaneous neurofibromas, 2.Numerous pigmented skin lesions ('cafe au lait' spots) 3. Pigmented iris hamaomas. Neurofibromatosis type 1 is a genetic disorder having a mutation in chromosome 17 while type 2 has a mutation in chromosome 22. MORPHOLOGIC FEATURES. Grossly, neurofibroma is an unencapsulated tumor producing a fusiform enlargement of the affected nerve. Neurofibromatosis in von Recklinghausen's disease is characterized by numerous nodules of varying size, seen along the small cutaneous nerves but may also be found in visceral branches of sympathetic nerves. Neurofibromatosis may involve a group of nerves or may occur as multiple, oval and irregular swellings along the length of a nerve (plexiform neurofibroma). TEXTBOOK OF PATHOLOGY 6th EDITION - HARSH MOHAN PAGE NO:893-894