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Familial medullary thyroid cancer without full MEN2 | CION Cancer Clinics
Some families with an inherited RET fault only ever see medullary thyroid cancer, with none of the adrenal or parathyroid problems of full MEN2. This used to be called familial medullary thyroid cancer. Specialists now treat it as a milder form of MEN2A, so the same checks still apply. This page explains why the label changed, how these families are found, and who should be tested. At CION Cancer Clinics, our oncologists explain what a gene result means for you and your family, and plan the checks that follow.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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On this page
- What is familial medullary thyroid cancer?
- How is it different from MEN2A, MEN2B and ordinary medullary cancer?
- How is a thyroid-only RET family usually found?
- What do the words you will hear mean?
- How has the advice for these families changed?
- What this page cannot tell you
- Four things families tell us, and what is actually true
- Common questions about familial medullary thyroid cancer
The short answer
What is familial medullary thyroid cancer?
It describes a family where an inherited RET fault causes medullary thyroid cancer, but nobody has had the adrenal or parathyroid problems seen in full MEN2. Specialists now treat it as a milder form of MEN2A rather than a separate condition. The practical point is simple: the other checks still happen.
Why the label changed
Families were once called FMTC because only thyroid cancer had appeared. Over time, some of those families went on to have an adrenal tumour in a younger relative. The label had given false comfort. Current guidance therefore files these families under MEN2A and screens them the same way, at a pace set by their codon.
How it usually behaves
Most families in this group carry moderate-risk RET faults. Thyroid cancer tends to appear later than in classic MEN2A, often in adult life, and it can be spread thinly across generations. That is why it is easy to miss.
Why families in India often do not know
Older relatives may have had neck surgery in another town, with the cancer type never written down or never explained. Some were simply told it was a goitre. When a younger relative is diagnosed, the family history can look empty. A little detective work with old papers often changes the picture.
A thyroid-only family history is still a RET family history.Telling them apart
How is it different from MEN2A, MEN2B and ordinary medullary cancer?
All four involve the same kind of thyroid cancer. What differs is whether it is inherited, and what else the family needs to watch for.
Thyroid-only family (FMTC)
An inherited RET fault, with medullary thyroid cancer as the only condition seen so far. Usually a moderate-risk codon and a later start.
Often looks like
- Thyroid cancer in two or more generations
- Diagnoses in middle age rather than childhood
- No adrenal or parathyroid problems recorded
MEN2A
An inherited RET fault causing thyroid cancer, and in some members an adrenal tumour or overactive parathyroid glands. FMTC now sits inside this group.
MEN2B
A rarer, earlier and more aggressive form, nearly always from one specific fault. Children often have distinctive features such as small bumps on the lips or tongue.
Sporadic medullary cancer
The most common picture. The RET fault, if there is one, is only inside the tumour. Nothing is passed on to children.
But note
- Some apparently sporadic cases are inherited
- Only a blood test can tell
Not sure whether this applies to you?
Ask an oncologistHow it comes to light
How is a thyroid-only RET family usually found?
One person is diagnosed
Someone is found to have medullary thyroid cancer, often after a neck lump or a raised calcitonin blood test. Few families suspect an inherited cause at this stage.
A germline RET test is offered
Guidelines advise a blood test for everyone with medullary thyroid cancer, whatever the family history. This is the step most often skipped.
The family history is looked at again
A counsellor asks about relatives who had thyroid cancer, neck surgery, or unexplained high blood pressure. Old pathology reports help most.
Relatives are tested for the known fault
Parents, brothers, sisters and children are offered a simpler, cheaper test for the one fault already found.
On your report
What do the words you will hear mean?
- Medullary thyroid cancer
- A cancer of the thyroid's C-cells. It is a different disease from the far more common papillary thyroid cancer.
- FMTC
- Familial medullary thyroid cancer. An older label for thyroid-only RET families, now grouped with MEN2A.
- MEN2
- Multiple endocrine neoplasia type two. Tumours in more than one hormone gland, driven by an inherited RET fault.
- Calcitonin
- A hormone made by C-cells. A raised level is the earliest sign of this cancer and the main follow-up test.
- CEA
- A second blood marker, used alongside calcitonin to follow the cancer.
- Germline
- Present in every cell from birth, so it can be passed on. Somatic means found only in the tumour.
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Side by side
How has the advice for these families changed?
When FMTC was a separate label
Current approach
Adrenal checks were sometimes skipped
Adrenal checks are done, timed by the codon
Diagnosis relied on how many relatives were affected
Diagnosis relies on the RET variant itself
Small families were hard to classify
One person's result is enough to start family testing
Surgery was often left until cancer appeared
Surgery is timed by the calcitonin trend
Being straight with you
What this page cannot tell you
It cannot tell you whether your family is a RET family. Thyroid cancer is common, and most of it is papillary cancer with no link to RET. Only the pathology report of the affected relative, and a blood test, can answer the question.
It cannot interpret your variant
What your specific variant means is a question for the counsellor who ordered the test. Some rare codons have been seen in only a handful of families. For those, evidence about timing is thin, and the plan leans more heavily on calcitonin.
Who this does not apply to
Most people with a thyroid nodule, or a relative with papillary thyroid cancer, do not need a RET test. A RET change found only in a tumour is also a different matter. It can guide drug treatment and is covered under targeted therapy.
If an older relative had "thyroid cancer" with no type recorded, try to find their hospital discharge papers. The word medullary is what you are looking for.Commonly believed
Four things families tell us, and what is actually true
"Our family only gets thyroid cancer, so we do not need adrenal tests."
That was the old thinking, and it proved unsafe. Adrenal tumours have appeared in families first labelled thyroid-only, so the checks continue at the pace your codon suggests.
"My mother had it at sixty, so it is not the inherited kind."
Late onset is typical of moderate-risk RET faults. Age alone does not rule out an inherited cause, which is why testing is offered to everyone with medullary cancer.
"Thyroid cancer is the easy cancer, so there is no hurry."
That reputation belongs to papillary cancer. Medullary cancer does not respond to radioactive iodine, so finding it early matters more.
"The tumour test was negative for RET, so the family is clear."
A tumour test and a blood test answer different questions. Only the blood test tells you about inheritance.
Questions we are asked
Common questions about familial medullary thyroid cancer
Is familial medullary thyroid cancer the same as MEN2A?
Current guidance treats it as a form of MEN2A. The family has an inherited RET fault, and so far only thyroid cancer has appeared. Because adrenal problems can still turn up later, the family is checked in the same way, at a pace set by the codon.
Nobody else in my family has had it. Should I still be tested?
Yes. Guidelines recommend a germline RET blood test for everyone diagnosed with medullary thyroid cancer. Some people with no family history turn out to carry an inherited fault, either because it arose new in them or because relatives were never diagnosed.
My relative had papillary thyroid cancer. Is that the same thing?
No. Papillary cancer is far more common and comes from different cells. It is not caused by germline RET faults. A family with several papillary cancers may still merit a conversation with a counsellor, but RET is not the gene being asked about.
Do my children need to be tested even if the cancer came late in our family?
Usually yes, and in childhood rather than adult life. RET is one of the few genes where testing a child genuinely helps, because thyroid checks and timely surgery prevent harm. Your counsellor will suggest when, based on your family's codon.
Will I need my whole thyroid removed?
For someone who carries a RET fault, surgeons usually remove the whole thyroid, because the C-cells are spread through both sides. Whether nearby lymph nodes are also removed depends on the calcitonin level and the ultrasound.
Why check for an adrenal tumour before surgery?
An adrenal tumour that has not been found can cause dangerous swings in blood pressure under anaesthetic. A simple blood or urine test rules it out beforehand. This applies to any operation, and to pregnancy, for anyone who carries a RET fault.
How is the cancer followed after surgery?
Mainly with calcitonin and CEA blood tests, and neck ultrasound when needed. A level that stays very low is reassuring. A rising level prompts scans. Thyroid hormone tablets are taken daily for life, and the dose is checked regularly.
Can counselling be done in Telugu?
Yes. Families can ask for the conversation, and the explanation of results, in Telugu. It often helps to bring the relative who was first diagnosed, along with any old reports, and the family member who will help make decisions.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
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Sources
- American Thyroid Association (Thyroid journal) — Revised American Thyroid Association Guidelines for the Management of Medullary Thyroid Carcinoma
- GeneReviews (NCBI) — Multiple Endocrine Neoplasia Type 2
- MedlinePlus Genetics — Multiple endocrine neoplasia
- MedlinePlus Genetics — RET gene
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
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Only thyroid cancer in your family, and not sure what it means?
Tell us who was diagnosed, with which type of thyroid cancer, and at what age. We will tell you honestly whether a RET test makes sense and arrange counselling if it does. One helpline serves every CION centre.