Multiple Endocrine Neoplasia Type 2B (MEN2B)

Multiple Endocrine Neoplasia Type 2B (MEN2B) is a rare genetic disorder that primarily affects the body's endocrine system, which controls hormone production. This condition causes the development of tumors in multiple glands, especially the thyroid gland and adrenal glands. People with MEN2B often develop a type of thyroid cancer called medullary thyroid carcinoma at a young age. It also causes growths on nerve tissue called mucosal neuromas, which can affect the lips, tongue, and digestive tract. Additionally, individuals may have a distinctive body appearance with a tall, thin build and curved spine. The disorder is caused by changes in a specific gene that affect how cells grow and divide.

Multiple Endocrine Neoplasia Type 2B (MEN2B) is an autosomal dominant syndrome characterized by the development of medullary thyroid carcinoma, pheochromocytoma, and mucosal neuromas. It results from activating mutations in the RET proto-oncogene, leading to constitutive activation of the RET tyrosine kinase receptor. This causes abnormal proliferation of neural crest-derived cells, particularly in the thyroid parafollicular C cells and adrenal medulla. Clinically, MEN2B presents with early-onset aggressive medullary thyroid carcinoma, often accompanied by bilateral pheochromocytomas causing hypertension. Patients also exhibit distinctive physical features such as marfanoid habitus and mucosal neuromas on the lips and tongue. The syndrome carries a high risk of morbidity and mortality without early diagnosis and treatment.