Type 2B multiple endocrine neoplasm

What are multiple? endocrine neoplasm syndromes?

Multiple Endocrine Neoplasia Syndromes (MEN) they are mainly hereditary diseases in which various endocrine glands develop benign (non-cancerous) or evil one (cancerous) tumors or hyperplasia (grow excessively without forming tumors).

There are 2 main types of MEN, MEN type 1 and MEN type 2. MEN type 2 is divided into 3 subtypes:

• MEN type 2A
• FMTC (family medullary thyroid carcinoma)
• MEN type 2B (previously known as MEN type 3).

Multiple endocrine neoplasia type 2B has additional features including mucous membrane neuromas (nerve tumors in the mucous membranes), neuromas in the intestine leading to gastrointestinal abnormalities, and a striking facial appearance associated with marfanoid habit (long, long, slender, slender fingers, and a high arched palate such as Marfan's disease). These characteristics may be the first sign from an intern malignancy and should provoke further investigation.

What is MEN disease type 2B?

Like MEN type 2A disease, MEN type 2B disease carries a high risk of developing medullary thyroid carcinoma and pheochromocytoma (a vascular tumor of the adrenal gland which can cause high blood pressure).

MEN type 2B disease is also characterized by the early development of multiple mucosal neuromas. Neuromas appear as:

• Bright bumps around the lips, tongue, and lining of the mouth
• Bumps on the eyelids that are often thickened; neuromas may also appear on the eyelid cornea and conjunctiva
• Growths in the gastrointestinal tract that can cause constipation, diarrhea, and, in some cases, an enlarged colon (megacolon).

Patients with MEN type 2B disease often also develop abnormalities of the spine and bone abnormalities in the feet and thighs. Many have long limbs and loose joints. These characteristics, together with thickened lips and eyelids, are associated with the marfanoid habit (Marfan's characteristics syndrome)

What is the cause of MEN type 2B disease?

In 95% cases, MEN type 2B disease is due to a mutation at tyrosine kinase RET domain gene at codon 918 in exon 16. The RET gene is a protocogene, which means that a mutation can predispose to the formation of cancers.

All MEN 2 subtypes are inherited in a autosomal The dominant way and the offspring of affected individuals have a 50% chance of inheriting the disease. However, not all cases of MEN type 2B are inherited, as there are some people with the disease who have no family history. Approximately 50% of affected individuals have been found to inherit the mutation from a parent and 50% has a new mutation.

* Image courtesy of Genetics 4 Medics

How was the diagnosis made?

The diagnosis of MEN type 2B is made clinically by the presence of:

• neuromas of the mucosa of the lips and tongue
• medullary corneal nerve fibers in the eye
• distinctive facies with enlarged lips
• aspheric habitus of the "marfanoid" body
• medullary thyroid carcinoma

Molecular genetic Tests can be used to confirm the diagnosis, for predictive testing, and to prenatal diagnosis.

What is the treatment for MEN type 2B disease?

People with MEN type 2B disease should have their thyroid gland removed at a very young age (about 1 year) to reduce the risk of thyroid. Cancer. Compared to other types of thyroid cancer, medullary thyroid carcinoma is a very aggressive cancer. If the thyroid is not removed in childhood, the average age of death in people with MEN type 2B disease is around 21 years. Once the thyroid is removed, patients must take thyroid hormone replacements (thyroxine) for the rest of their lives.

There is no known cure for any of the MEN syndromes. Patients are treated for their symptoms. Annual biochemical urine screening for pheochromocytoma is recommended for all patients. Genetic testing is also important for people with a family history of the disease, as early diagnosis and treatment will reduce the risk of thyroid cancer and death.