Multiple endocrine neoplasia (MEN) syndromes
The term multiple endocrine neoplasia (MEN) refers to a group of several different, hereditary syndromes that are inherited in families. The basic link of all syndromes is the simultaneous existence of a large number of tumors of different endocrine glands, although not all tumors have to be clinically expressed, but there may be overlaps between individual syndromes. The symptoms of the disease are caused by excessive production of hormones from the affected organs or local pressure of the tumor on other organs. The diagnosis is made by a specialist examination with indispensable methods of laboratory determination of hormones, genetic testing and the use of radiological and nuclear medicine imaging examinations such as CT and MR. Treatment is always primarily surgical with secondary application of various conservative methods of disease symptom control, according to each individual diagnosis.
Division of syndromes
- Multiple endocrine neoplasia type 1 syndrome (MEN1) or Wermer's syndrome is characterized by the presence of tumors of the pituitary gland, parathyroid glands and cells of the islets of Langerhans of the pancreas. In 70% - 95% of patients, it is possible to confirm a mutation of the tumor-suppressor gene MEN1, which codes for the formation of the menin protein responsible for tumor growth. Also, other accompanying tumors can be diagnosed, such as tumors of the meninges (meningoma), fat tissue (lipoma), blood vessels and connective tissue (angiofibromas), stomach and bronchus carcinoids. Clinically, MEN1 syndrome is most often presented by excessive function of the pituitary gland, i.e. hyperpituitarism (pituitary tumors that secrete prolactin, growth hormone and corticotropin), excessive function of the parathyroid glands (hyperparathyroidism) and the finding of pancreatic tumors (insulinoma and glucagonoma) with associated symptoms of the aforementioned disorders.
- Multiple endocrine neoplasia syndrome type 2A (MEN2A) or Sipple's syndrome is characterized by the presence of medullary thyroid carcinoma, adrenal medulla carcinoma (phaeochromocytoma) and increased function of the parathyroid glands (hyperparathyroidism). The clinical presentation corresponds to the symptoms of the mentioned disorders. In most patients, it is possible to confirm mutations in the RET proto-oncogene by genetic testing.
- Multiple endocrine neoplasia syndrome type 2B (MEN2B) is characterized by the existence of numerous nerve tumors (neurinomas) in the mucous membrane area, medullary carcinoma of the thyroid gland and carcinoma of the medulla of the adrenal gland (phaeochromocytoma) with impaired growth and development (marfanoid habitus). In the majority of patients, genetic testing can prove mutations in the RET proto-oncogene (M918T mutation in as many as 95% of patients).