MEN 2B Syndrome

Multiple endocrine neoplasia type 2B caused by RET proto-oncogene mutation.

Written by: Saygı Hospital Health Guide Editorial Board

Last updated: June 10, 2026

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Endokrinoloji department. Book Appointment →

What is MEN 2B Syndrome?

Multiple endocrine neoplasia type 2B (MEN 2B) is an autosomal dominant tumor syndrome caused by germline mutations of the RET proto-oncogene, most often the M918T mutation. It accounts for the smallest proportion of MEN 2 cases but is the most aggressive subtype.

Medullary thyroid carcinoma (MTC) develops at very young ages (often within the first year), and approximately 50% of cases also have pheochromocytoma. In addition, mucosal neuromas, marfanoid habitus, ganglioneuromatosis of the gastrointestinal tract and skeletal abnormalities are seen.

Diagnosis relies on RET genetic testing. According to international guidelines (ATA), prophylactic total thyroidectomy is recommended within the first year of life, often during the neonatal period. Lifelong endocrine surveillance is essential.

Symptoms

Mucosal neuromas (lip, tongue)

Marfanoid habitus

Symptoms of medullary thyroid carcinoma

Hypertensive crises (pheochromocytoma)

Constipation (intestinal ganglioneuromatosis)

Skeletal abnormalities

Loss of pupillary reflex

Risk Factors

RET M918T mutation

Autosomal dominant inheritance

Family history

De novo mutation (about 50%)

Other RET mutations

MEN 2B parent

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

Marfanoid habitus and mucosal neuromas
Newly detected thyroid mass
Hypertensive crises and palpitations
Persistent constipation in childhood
Family history of MEN 2B
Suspicion on RET genetic test

Treatment Methods

Prophylactic thyroidectomy (within first year)

Pheochromocytoma resection

Calcitonin and CEA monitoring

Annual surveillance with neck ultrasound

Genetic counseling and family screening

Multidisciplinary endocrine follow-up

Which Department to Visit?

You can visit our Endokrinoloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

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Let us help you

You can make an appointment with our specialists or contact us for your concerns.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.