Multiple Endocrine Neoplasia
Multiple endocrine neoplasia (MEN) is a hereditary condition, where an individual may have developed tumors in one or more endocrine glands. Endocrine glands are the glands that secrete hormone into the blood directly rather than secreting into a duct. Tumors can be benign (noncancerous) or malignant (cancerous). The glands that are commonly affected include pituitary, thyroid, parathyroid, adrenal, and pancreas.
The major types of MEN syndromes are MEN type I and MEN type II.
Multiple endocrine neoplasia type I – It is caused by a defect in the gene coding for the protein menin, which is located on chromosome 11. The tumor commonly affects the parathyroid, pancreas, and pituitary glands. The common symptoms include abdominal pain, black stools, headache, burning sensation in upper abdomen, loss of appetite, weakness, loss of muscle coordination, and nausea and vomiting. The tumor can be diagnosed by tests such as abdominal CT and MRI scan, blood tests, and parathyroid biopsy.
- If the tumor has affected the pituitary gland then anti-cancer drugs are given to prevent the tumor growth and to reduce the prolactin level. Prolactin is a peptide hormone produced by the pituitary gland
- If the tumor has affected the parathyroid gland then the entire gland may be removed. Parathyroid gland controls the calcium production and if these glands are removed the body will not be able to produce calcium which may lead to formation of kidney stones, thinning of bone, and high blood pressure. Hence the total removal of the gland is not done initially. If the entire gland is removed during the surgery, your doctor may suggest for hormone replacement therapy
- Your doctor may prescribe certain medicines to lower the production of gastric acid produced by some tumors and to reduce the risk of ulcers
Multiple Endocrine neoplasia (MEN) type II – It is caused by a defect in the RET gene. It commonly causes medullary carcinoma in the thyroid gland. Pheochromocytoma (adrenal gland tumor) may be seen in nearly half of the patients and some patients may also have hyperplasia of parathyroid gland.
Multiple endocrine neoplasia type II is subdivided into three types, MEN IIa, MEN IIb, and familial medullary thyroid carcinoma (FMTC). The MEN type IIa is most commonly occurring subtype where medullary carcinoma occurs in early stages of adulthood, some of the individuals develop pheochromocytoma and some develop hyperparathyroidism. In MEN type IIb the medullary carcinoma occurs in the early childhood and some individuals develop pheochromocytoma but hyperparathyroidism may not be observed. In FMTC, medullary carcinoma occurs in several members of the same family without the occurrence of pheochromocytoma and hyperparathyroidism.
The most common symptoms include tumor pressing on the nearby structures, breathing problems, cough, diarrhea, abdominal pain, chest pain, nervousness, palpitations, irritability and weight loss. Type II MEN disorder can be diagnosed by physical examination and diagnostic tests such as abdominal CT and MRI scan, thyroid scan, ultrasound scan, and biopsies of the glands.
Surgery is done to remove the tumor in the adrenal gland. Medullary carcinoma is treated by removal of the thyroid gland and the surrounding lymph nodes. Your doctor may suggest hormone replacement therapy if the entire thyroid gland is removed. Early diagnosis and surgery can cure the disease condition. If the child is a carrier of RET gene, then thyroid gland is surgically removed before it becomes cancerous.
The purpose of hormone replacement therapy is to compensate for the thyroid hormones that are lost when the thyroid glands are removed because of which the body will no longer be able to produce thyroid hormones, leading to hypothyroidism. Thyroid hormones help to control body metabolism, when the hormone level is reduced the metabolism rate will be impaired. Hormone replacement therapy can address the issue of hypothyroidism.