Re: Neurofibromatoza

Nelson Textbook of Pediatrics 19th Edition (actual. 2013)
Part XXVII - The Nervous System
Chapter 584 - Neurologic Evaluation
Chapter 585 - Congenital Anomalies of the Central Nervous System
Chapter 589 - Neurocutaneous Syndromes
589.1 Neurofibromatosis


Clinical Manifestations and Diagnosis

NF-1 is the most prevalent type, with an incidence of 1/3,000, and is diagnosed when any 2 of the following 7 features are present: (1) Six or more café-au-lait macules over 5 mm in greatest diameter in prepubertal individuals and over 15 mm in greatest diameter in postpubertal individuals. Café-au-lait spots are the hallmark of neurofibromatosis and are present in almost 100% of patients. They are present at birth but increase in size, number, and pigmentation, especially during the first few yrs of life (Fig. 589-1). The spots are scattered over the body surface, with predilection for the trunk and extremities but sparing the face. (2) Axillary or inguinal freckling consisting of multiple hyperpigmented areas 2-3 mm in diameter. Skinfold freckling usually appears between 3 and 5 yr of age. The frequency of axillary and inguinal freckling has been reported to be greater than 80% by 6 yr of age. (3) Two or more iris Lisch nodules. Lisch nodules are hamartomas located within the iris and are best identified by a slit-lamp examination (Fig. 589-2). They are present in >74% of patients with NF-1 but are not a component of NF-2. The prevalence of Lisch nodules increases with age, from only 5% of children <3 yr of age, to 42% among children 3-4 yr of age, and virtually 100% of adults ≥21 yr of age. (4) Two or more neurofibromas or 1 plexiform neurofibroma. Neurofibromas typically involve the skin, but they may be situated along peripheral nerves and blood vessels and within viscera including the gastrointestinal tract. These lesions appear characteristically during adolescence or pregnancy, suggesting a hormonal influence. They are usually small, rubbery lesions with a slight purplish discoloration of the overlying skin. Plexiform neurofibromas are usually evident at birth and result from diffuse thickening of nerve trunks that are frequently located in the orbital or temporal region of the face. The skin overlying a plexiform neurofibroma may be hyperpigmented to a greater degree than a café-au-lait spot. Plexiform neurofibromas may produce overgrowth of an extremity and a deformity of the corresponding bone. (5) A distinctive osseous lesion such as sphenoid dysplasia (which may cause pulsating exophthalmos) or cortical thinning of long bones (e.g., of the tibia) with or without pseudoarthrosis. (6) Optic gliomas are present in approximately 15% of patients with NF-1 and represent mostly low-grade astrocytomas. They are the main CNS tumor with a marked increased frequency in NF-1. Because of their growth, it is recommended that all children age 10 yr or younger with NF-1 undergo annual ophthalmologic examinations. When they progress, visual symptoms are produced because the tumors enlarge and put pressure on the optic nerves and chiasm resulting in impaired visual acuity and visual fields. Extension into the hypothalamus can lead to endocrine deficiencies or failure to thrive. The MRI findings of an optic glioma include diffuse thickening, localized enlargement, or a distinct focal mass originating from the optic nerve or chiasm (Fig. 589-3). (7) A first-degree relative with NF-1 whose diagnosis was based on the aforementioned criteria.

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