Multiple Endocrine Neoplasia Type II


Multiple endocrine neoplasia type II (MEN II) is rare genetic condition in which tumours (see entry Cancer) develop in one or more of the endocrine glands. Endocrine glands release hormones (chemical messages) into the bloodstream. The endocrine glands most commonly involved include:

  • thyroid gland
  • adrenal gland
  • parathyroid gland

Onset of MEN II symptoms may occur at any age.


Last updated October 2018 by Professor RV Thakker, Academic Endocrine Unit, University of Oxford, Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), Churchill Hospital, Oxford, UK.

Although great care has been taken in the compilation and preparation of all entries to ensure accuracy, we cannot accept responsibility for any errors or omissions. Any medical information provided is for education/information purposes and is not designed to replace medical advice by a qualified medical professional.

What are the symptoms?

There are three types of MEN II including multiple endocrine neoplasia type IIA (MEN IIA now also called MEN2); multiple endocrine neoplasia type IIB (MEN IIB now also called MEN3) and familial medullary thyroid cancer (FMTC).

Multiple endocrine neoplasia type IIA
There are three types of growth that can occur in MEN IIA. These occur in the ‘butterfly-shaped thyroid’ gland in the neck, the parathyroid glands that lie close to or within the thyroid, and in the adrenal glands that sit on top of each kidney. Pheochromocytoma is a rare tumour of adrenal gland tissue. It results in the release of too much epinephrine and norepinephrine, hormones that control heart rate, metabolism, and blood pressure. Although most of the growths are benign (non-cancerous), the growth in the thyroid gland is always cancerous (medullary thyroid cancer or MTC).

Multiple endocrine neoplasia type IIB
There are two main growths common to MEN IIB. These occur in the thyroid gland in the neck, and in the adrenal glands that sit on top of each kidney. The growth in the thyroid gland is always cancerous (medullary thyroid cancer or MTC) and is more aggressive in MEN IIB than in the other types of MEN.

FMTCis a rare inherited form of cancer of the thyroid gland in the neck (medullary thyroid cancer or MTC). MTC may also occur alone and independently of FMTC/MEN II.

What are the causes?

The cause of MEN II is a change (mutation) in a gene called RET. This mutation causes many tumours to appear in the same person, but not necessarily at the same time.

How is it diagnosed?

  • Genetic testing is used to identify members of a family known to be affected with MEN II.
  • Blood tests for hormone levels as well as scans of the neck are used to check for growths.

How is it treated?

Surgery is needed to remove pheochromocytoma (rare tumour of adrenal gland tissue).

For medullary carcinoma of the thyroid, the thyroid gland and surrounding lymph nodes must be totally removed. Thyroid hormone replacement therapy is given after surgery. If the medullary thyroid carcinoma cannot be removed completely or if it has spread, then medicines that may prevent its growth can be used.

If a child is known to carry the RET gene mutation, surgery to remove the thyroid before it becomes cancerous is considered. This should be discussed with a physician and surgeon who are very familiar with this condition. It would be done at an early age (before age 5) in people with known MEN IIA, and before age 12 months in people with MEN IIB.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
All MEN II subtypes are inherited as an autosomal dominant trait. Affected families should be referred to a genetics centre for information and advice.

Prenatal diagnosis
This may be possible if the genetic mutation causing MEN II in a family is known.

Is there support?

AMEND (Association for Multiple Endocrine Neoplasia Disorders)

Tel: 01892 516076

The Organisation is a Registered Charity in England and Wales No. 1099796, established in 2002. It is a patient support group run by volunteers for the benefit of everyone affected by multiple endocrine neoplasia disorders and their associated endocrine growths. The Organisation runs a UK research registry and produces patient information with the help of an expert medical advisory team, including information for children. Membership is free and open to patients and health professionals.

Group details last confirmed October 2018.

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