Saturday, September 28, 2019

Plexiform neurofibromatosis Essay Example | Topics and Well Written Essays - 1000 words

Plexiform neurofibromatosis - Essay Example Neurocutaneous disorders are diseases that involve nervous system, skin, and retina and other ectodermal tissues. They are congenital. Migration of neural cells to brain and melanoblasts to the skin from the neural crest occurs between 3 to 6 months of intrauterine life. A disturbance of this migration results in neurocutaneous syndromes involving ectodermal and neuroectodermal elements (Panda 526). Neurofibromatosis is an autosomal dominant neurogenetic disorder. It can present with spectrum of symptomatology, it affects bone, nervous system, soft tissue and the skin. There are two varieties of neurofibromatosis, NF-1, popularly known as peripheral neurofibromatosis and NF-2, also known as central neurofibromatosis. A third variant is known as segmental neurofibromatosis. However, NF-1 has often central features. Here, the discussion will be limited to NF-1 which can present as plexiform neurofibromatosis.Increased nerve growth stimulating activity is incriminated for the development of neurofibromatosis. The disease has a genetic basis. NF-1 is linked to a large gene on band 17q 11.2. It encodes a protein termed neurofibromin.The protein has been found essential for the negative regulation of Ras, suggesting that neurofibromin acts as a tumor suppressor. Truncations in neurofibromin led to the mutations in most of the NF-1 cases. NF-1 is a disorder with variable phenotypic expression. Some patients may have only cutaneous expression, while others may have life threatening and disfiguring complications. These variations are demonstrated even with in the families. The disease also tends to change and develop with time. Many different mutations with in neurofibromatosis gene have been described. Spontaneous Manimunda mutations are thought to contribute to approximately 30-50% of neurofibromatosis cases. The world wide prevalence of this disease is 1 in 2500 to 3300 live births. All race groups are equally affected and there is no sexual preponderance (Kam and Helm). Most patients with neurofibromatosis present with caf au lait macules during first three years of life. Neurofibromas develop during late adolescence. Few may present with complications like pain caused by neurofibromas, pathological fractures or hypertensive head ache caused by pheochromocytoma. Physical examination may reveal the involvement of different organs and systems. Caf au lait spots are unusual pigmentary patterns, irregularly shaped, evenly pigmented, brown macules. Most individuals with neurofibromatosis have 6 or more spots that are 1.5cm or greater in diameter. In young children, 5 or more caf au lait macules greater than 0.5 cm in diameter are suggestive of neurofibromatosis. 1 or 2 caf au lait macules are encountered even in healthy individuals. Lisch nodules are hamartomas of the iris that appears dome shaped. Slit lamp examination will reveal this and help in confirming the diagnosis of neurofibromatosis. Axillary freckling (as well as inguinal freckling) known as Crowe sign is a useful diagnostic feature in neurofibromatosis. They develop during puberty. Areas of freckling and hypertrichosis occasionally overlay plexiform neurofibromas. Bone involvement can include pseudoarthrosis of tibia, bowing of long bones and orbital defects. Occasionally pulsating exophthalmos is encountered. Neurofibromas are the most

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