(The mucosal neuro Matoses syndrome, multiple endocrine adenomatosis type 2B)

A multiple endocrine neoplasia type 2B (MEN 2B) is an autosomal dominantly inherited disease, which is characterized by medullary thyroid carcinoma, pheochromocytoma, mucosal neuromas more and intestinal ganglioneuromas, and often due to a marfanoid habitus and other skeletal abnormalities. The symptoms vary depending on the involved glands. Diagnosis and treatment are as in MEN 2A.

90% of the MEN-2B cases result from a single amino acid substitution in the RET protein. As with MEN 2A and inherited medullary thyroid carcinomas, this mutation leads to activation of RET proto-oncogene-mediated cellular processes. More than 50% are de novo mutations and therefore may be more sporadic than inherited.

A multiple endocrine neoplasia type 2B (MEN 2B) is an autosomal dominantly inherited disease, which is characterized by medullary thyroid carcinoma, pheochromocytoma, mucosal neuromas more and intestinal ganglioneuromas, and often due to a marfanoid habitus and other skeletal abnormalities. The symptoms vary depending on the involved glands. Diagnosis and treatment are as in MEN 2A. 90% of the MEN-2B cases result from a single amino acid substitution in the RET protein. As with MEN 2A and inherited medullary thyroid carcinomas, this mutation leads to activation of RET proto-oncogene-mediated cellular processes. More than 50% are de novo mutations and therefore may be more sporadic than inherited. Symptoms and discomfort symptoms and clinical signs reflect the glandular disorders resist (findings associated with MEN syndromes). Approximately 50% of patients have the complete syndrome with neuromas of the mucosa, pheochromocytomas and medullary thyroid carcinoma (MTC). Less than 10% have only neuromas and pheochromocytomas, while the remaining patients neuromas and MTC without showing pheochromocytoma. Neuromas of the mucosa are very often the first clinical signs and occur in almost all patients. Neuromas appear as shiny bumps on the lips, tongue or the buccal mucosa. They also develop frequently on the eyelids, the conjunctiva and the cornea; Children often can not produce tears. Thickened eyelids and inverted, diffusely hypertrophied lips are characteristic. Disorders in the gastrointestinal tract, caused by changes in motility (constipation, diarrhea and occasionally a megacolon), are common. They probably result from an intestinal ganglioneuromatosis. Patients almost always have a marfanoid habit. Skeletal abnormalities are common, including malformations of the spine (lordosis, kyphosis, scoliosis), “slipped capital femoral epiphyses” dolichocephaly (ship-shaped skull, also referred to as Scaphocephalie), hollow foot and clubfoot. MTC and pheochromocytoma meet the manifestations in MEN IIA syndrome. Both often occur bilaterally and multicentric. MTC in MEN-2B tends to be particularly aggressive, and already occurs in small children. Although neuromas, characteristic changes in the face and gastrointestinal disorders are very early presence, the syndrome is often not detected until it comes later in the manifestation of MTC or pheochromocytoma. Diagnosis Clinical suspicion genetic testing levels of free Metanephrine in plasma and urine catecholamine in the localization of pheochromocytoma with MRI or CT Suspected MEN 2B, patients with a positive family history of MEN 2B, pheochromocytoma, multiple mucosal neuromas or MTC. The genetic test is very accurate and is done to confirm the disorder. Genetic tests are also carried out to investigate 1st degree and all symptomatic family members of patients with MEN 2B, as well as with MEN 2A (multiple endocrine neoplasia type 2A (MEN 2A): screening process). The suspicion of a pheochromocytoma may be clinically justified and is confirmed by measurements of free and Plasmametanephrins of catecholamines in urine confirmed (pheochromocytoma diagnosis). Laboratory tests on MTC can be performed (Medullary thyroid carcinoma). The MRI or CT is used to search for pheochromocytomas and MTC. Therapy Surgical excision of tumors diagnosed Prophylactic thyroidectomy Affected patients should as soon as the diagnosis is made to undergo a total thyroidectomy. If a pheochromocytoma exists, it should be removed before thyroidectomy. Gene carriers should receive prophylactic thyroidectomy before the age of one year. Conclusion MEN 2B has a mutation in the same gene as with MEN 2A and manifests similar, except for the absence of hyperparathyroidism, the presence of a more aggressive MTC and the presence of multiple mucosal neuromas, as well as a marfanoid habitus. Patients should perform genetic tests on RET proto-oncogene mutations and blood or urine tests for pheochromocytoma. A pheochromocytoma is removed and carried out a prophylactic thyroidectomy.

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