Multiple endocrine neoplasia type 2B

Multiple endocrine neoplasia type 2B, or MEN 2B, is a genetic disease that causes multiple tumors on the mouth, eyes and endocrine glands. It is the most severe form of multiple endocrine neoplasia and is set apart by benign oral and submucosal tumors alongside endocrine malignancies. It is caused by the pathogenic variant p.Met918Thr in the RET gene, which can lead to medullary thyroid cancer and pheochromocytoma. Affected people tend to be tall and lanky with an elongated face and enlarged lips, and symptoms usually appear before the age of ten. Medullary thyroid cancer almost always occurs and can be aggressive, while adrenal pheochromocytoma occurs in about half of cases. Wagenmann described it in 1922, and it was recognized as a syndrome in 1965 and 1966. Estimated prevalence is between one in 600,000 and one in 4,000,000.