Multiple Endocrine Neoplasia Syndrome

Multiple Endocrine Neoplasia Syndrome

Summarize

Multiple Endocrine Neoplasia (MEN) syndrome is a genetic disorder affecting the endocrine system. The endocrine system consists of glands and cells that produce hormones and release them into the bloodstream. MEN syndrome can lead to hyperplasia (excessive growth of normal cells) or tumors, which may be benign (non-cancerous) or malignant (cancerous).

Epidemiological

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Etiology & Risk Factors

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Classification & Staging

Multiple endocrine neoplasia syndrome comes in several types, each of which can lead to different diseases or cancers. Genetic counseling and testing should be conducted for high-risk patients and family members to determine if they have the syndrome.

 

        There are two main types of MEN syndrome: type 1 and type 2:

 

 

Multiple Endocrine Neoplasia Syndrome Type 1, also known as Werner syndrome, typically results in tumors of the parathyroid glands, pituitary gland, and pancreas. In rare cases, it can also lead to tumors in the adrenal glands, gastrointestinal tract, fibrous tissue, and fat cells. These tumors produce excessive hormones, which can cause various symptoms depending on the type of hormone. ​ The most common symptom of Multiple Endocrine Neoplasia Syndrome Type 1 is hypercalcemia, which occurs when the parathyroid glands produce too much parathyroid hormone. The signs and symptoms of hypercalcemia include:

o lack strength

o feeling of fatigue 。

o Nausea and vomiting

o anorexia

o Very thirsty

o Increased urination.

o astriction

Diagnosis of multiple endocrine neoplasia syndrome type 1 usually requires the discovery of tumors in two different locations. Prognosis (chance of recovery) is generally good.

Children diagnosed with type 1 multiple endocrine neoplasia syndrome need to be checked for signs of cancer starting at age 5 and continuing throughout life. Parents are advised to talk to their child's doctor about the cancer tests and examinations that should be done and how often they should be done.

Children with type 1 multiple endocrine neoplasia syndrome may also have primary hyperparathyroidism. In this condition, one or more parathyroid glands produce excessive parathyroid hormone. The most common symptom of primary hyperparathyroidism is kidney stones. If a child has primary hyperparathyroidism, they can undergo genetic testing to check for gene changes associated with type 1 multiple endocrine neoplasia syndrome.

 

Type 2 multiple endocrine neoplasia syndrome includes three subgroups: type 2 multiple endocrine neoplasia syndrome 2A, familial medullary thyroid carcinoma and type 2 multiple endocrine neoplasia syndrome 2B. Among them, familial medullary thyroid carcinoma is a special type of type 2 multiple endocrine neoplasia syndrome 2A.

 

O Multiple endocrine neoplasia syndrome type 2A

Multiple Endocrine Neoplasia Syndrome Type 2A, also known as SIPPLE syndrome, can be diagnosed when a patient or a parent, sibling or child of the patient has two or more of the following conditions:

 medullary carcinoma of thyroid gland 。

Pheochromocytoma (an adrenal tumor).

Parathyroid disease (benign tumor of the parathyroid gland or enlargement of the parathyroid gland)

Signs and symptoms of medullary thyroid carcinoma may include:

• Swelling in the throat or neck.

• expiratory dyspnea 。

• dysphagia 。

• hoarseness 。

Signs and symptoms of pheochromocytoma may include:

• Abdominal or chest pain

• Strong, rapid or irregular heartbeat

• headache

• Excessive sweating for unknown reasons

• dizzy

• Feeling shaky

• Irritable or nervous

Signs and symptoms of parathyroid disease may include:

• hypercalcinemia

• Persistent pain in the abdomen, side or back

• ostalgia

• cataclasis

• Neck mass

• Changes in voice, such as hoarseness

• dysphagia

        If there are multiple endocrine neoplasia syndrome type 2A patients in the family, family members should be counseled about genetic testing and early screening for children under age 5 for genetic variants that cause this type of cancer.

        A few cases of medullary thyroid carcinoma may co-occur with congenital megacolon, also known as Hirschsprung's disease, which is a chronic constipation condition that begins in infancy. This phenomenon has been observed in families with multiple endocrine neoplasia syndrome type 2A. Congenital megacolon may precede other symptoms of multiple endocrine neoplasia syndrome type 2A. Patients diagnosed with congenital megacolon should be screened for genetic changes that can cause multiple endocrine neoplasia syndrome type 2A.

        Familial medullary thyroid carcinoma (FMTC) is a type 2A multiple endocrine neoplasia syndrome that causes medullary thyroid carcinoma. A diagnosis of familial medullary thyroid carcinoma can be made when two or more family members have medullary thyroid carcinoma and no other family members have parathyroid or adrenal problems.

 

O Multiple endocrine neoplasia syndrome type 2B

Patients with type 2B multiple endocrine neoplasia syndrome may have a thin body shape, long arms, and legs. Because of benign tumors on the mucous membranes, patients may have thick lips and uneven skin on the lips. Type 2B multiple endocrine neoplasia syndrome may cause the following diseases:

• medullary carcinoma of thyroid gland

• parathyroid hyperplasia

• adenoma

• chromaffin tumor

• Neurocytoma of the mucosa or other sites

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Examination & Diagnosis

The diagnosis and staging of multiple endocrine neoplasia syndrome depends on physical signs and symptoms as well as the patient's family history. It may include:

Physical examination and medical history

 blood chemical examination

 ultrasonic examination

MRI (magnetic resonance imaging)

CT scan

PET scan

Fine needle aspiration (FNA) or surgical biopsy

        For a description of these tests and procedures, see the basic information section above.

 

        Other detection methods used to diagnose multiple endocrine neoplasia syndrome include:

Genetic testing: A laboratory test that analyzes cells or tissues for changes in genes, chromosomes or proteins. These changes may be a sign of a genetic disease or may be associated with an increased risk of a particular disease or condition.

Blood hormone testing involves examining blood samples to measure the levels of certain hormones released into the bloodstream by organs and tissues. Abnormal levels (either higher or lower than normal) of a substance may indicate a disease in the organ or tissue that produces it. When diagnosing multiple endocrine neoplasia syndrome, doctors may order tests to check for abnormal levels of thyroid-stimulating hormone (TSH) in the blood. TSH is produced by the pituitary gland in the brain, which stimulates the release of thyroid hormones and controls the growth rate of thyroid follicular cells. In diagnosing multiple endocrine neoplasia syndrome, tests may also be conducted to check for abnormally high levels of calcitonin or parathyroid hormone (PTH) in the blood.

Radioactive iodine scanning (RAI scanning) is a test that identifies areas within the body where thyroid cancer cells are rapidly dividing. Radioactive iodine (RAI) is used because only thyroid cells can absorb it. The patient ingests a small amount of radioactive iodine, which is then distributed through the bloodstream and absorbed by thyroid tissue and cancer cells throughout the body. Abnormal thyroid cells absorb less iodine than normal cells. Areas that do not absorb iodine are called 'cold spots.' In the scan images, these cold spots appear lighter. These spots can be benign (not cancerous) or malignant, so a biopsy is necessary to determine if they are cancerous.

Sestamibi scan: This is a radiolabeled scanning technique used to detect overactive parathyroid glands. A very small amount of the radioactive substance, technetium-99, is injected into the vein and travels through the bloodstream to the parathyroid glands. The radioactive material accumulates in the overactive glands and appears as bright spots on a special camera that detects radioactivity.

Angiography: A method of observing blood vessels and blood flow. Contrast is injected into the blood vessel. As the contrast passes through the blood vessel, X-rays are taken to see if there is a blockage in the blood vessel.

Venous sampling for hyperparathyroidism involves taking blood samples from veins near the parathyroid glands to measure the amount of parathyroid hormone released into the bloodstream by each gland. If a blood test indicates hyperparathyroidism but imaging does not identify which gland is overactive, venous sampling can be performed from the area around the gland.

Somatostatin receptor imaging: This is a radiopharmaceutical scan used to detect tumors. A very small amount of the radioactive hormone octreotide, which binds to tumors, is injected into a vein and circulated throughout the body via the bloodstream. Octreotide attaches to tumors and is detected using a specialized camera to map their location in the body. This test is also known as an octreotide scan or SRS.

MIBG scan: This test is used to detect neuroendocrine tumors, such as pheochromocytoma. A very small amount of a substance called radioactive MIBG is injected into the vein and circulated throughout the body via the bloodstream. Neuroendocrine tumor cells absorb the radioactive MIBG, which can then be detected by a scanner. The scan typically takes at least 1-3 days. Patients may take iodine solution before or during the test to prevent the thyroid from absorbing too much MIBG.

24-hour urine test: A 24-hour urine is collected to measure the levels of catecholamines and their breakdown products in the urine. Abnormal levels (higher or lower than normal) may indicate organ or tissue diseases. Levels higher than normal can be a sign of a pheochromocytoma.

Five peptide gastrin stimulation test: This test involves examining blood samples to measure the level of calcitonin in the blood. Calcium gluconate and five peptide gastrin are injected into the bloodstream, and several blood samples are taken over the next 5 minutes. If the blood shows elevated levels of calcitonin, it may indicate medullary thyroid cancer.

Clinical Management

Multiple endocrine neoplasia syndrome comes in several types, each of which may require different treatments:

Patients with type 1 multiple endocrine neoplasia syndrome require treatment for parathyroid, pancreatic and pituitary tumors.

Patients with type 1 multiple endocrine neoplasia syndrome and primary hyperparathyroidism can have at least three parathyroid glands and thymus surgically removed.

Patients with type 2A multiple endocrine neoplasia syndrome, if genetic tests show a specific mutation in the RET gene, usually need to have their thyroid removed surgically before age 5. The purpose of the surgery is to diagnose cancer or prevent it from forming or spreading.

Infants with type 2B multiple endocrine neoplasia syndrome may need surgery to remove the thyroid gland to prevent cancer.

Children with both medullary thyroid cancer and multiple endocrine neoplasia syndrome type 2B can be treated with targeted therapy (using kinase inhibitors).

Patients with congenital megacolon and certain genetic changes may need to have their thyroid removed to prevent cancer.

 

Children with recurrent multiple endocrine neoplasia syndrome may be considered for clinical trials to test whether genes in the patient's tumor samples have changed and to target the patient based on the type of gene change.

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Follow-up & Review

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Daily Care

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Cutting-edge therapeutic and clinical Trials

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