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ENT endocrine disorders > Endocrine multiple endocrine neoplasia syndrome > Flashcards

Endocrine multiple endocrine neoplasia syndrome Flashcards

1
Q

Which of the MEN subtypes includes involvement

of the parathyroid glands?

A

MEN 1 patients have multiglandular disease requiring subtotal parathyroidectomy. MEN-2A patients have a parathyroid adenoma or multiglandular disease and primary hyperparathyroidism. There is no parathyroid involvement in MEN-2B or familial non-MEN medullary thyroid carcinoma.

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2
Q

How does hyperparathyroidism manifest in patients with MEN-2A?

A

About 15 to 30% of patients with MEN-2A develop primary hyperparathyroidism, which is typically mild or asymptomatic clinically. It can manifest as single parathyroid adenoma or multiple gland hyperplasia. The average age of
onset is age 38 years, and it is usually present many years
after diagnosis of medullary thyroid carcinoma.

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3
Q

Which subtype of medullary thyroid carcinoma is

more common, sporadic or familial?

A

Sporadic cases represent 75% of medullary thyroid carcinomas.

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4
Q

What are the different subtypes of familial

medullary thyroid carcinoma?

A

MEN-2A and MEN-2B. Additionally, there are several rare

types of familial non-MEN medullary thyroid carcinoma.

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5
Q

What conditions are associated with MEN-2A syndrome?

A

Medullary thyroid carcinoma, pheochromocytoma, and

parathyroid hyperplasia

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6
Q

What conditions are associated with MEN-2B syndrome?

A

Medullary thyroid carcinoma, pheochromocytoma, marfanoid body habitus, and mucosal neuromas

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7
Q

What is the inheritance pattern of familial medullary thyroid carcinoma?

A

Autosomal dominant

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8
Q

What gene mutation(s) are responsible for familial medullary thyroid carcinoma?

A

Gain of function mutations of the RET proto-oncogene

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9
Q

What is the most common subtype of familial

medullary thyroid carcinoma?

A

MEN-2A is most common, followed by familial non-MEN

and then MEN-2B.

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10
Q

Which form of medullary thyroid carcinoma is the

most aggressive?

A

MEN-2B is most aggressive, followed by sporadic cases,
then MEN-2A, then familial non-MEN, which has the best
prognosis.

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11
Q

What is the recommended treatment for patients

with a RET mutation and/or a family history of medullary thyroid carcinoma?

A

For children, prophylactic thyroidectomy is the recommended treatment. In general, early intervention improves outcome by preventing metastases. In MEN-2A, thyroidectomy is recommended in pre-teenage patients, whereas in MEN-2B, resection is recommended in infancy, often before
the age of 1 year.

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12
Q

What gene is involved in MEN-2?

A

MEN-2 has three clinical subtypes: MEN-2A, MEN-2B, and
familial medullary thyroid carcinoma (FMTC). All are
associated with mutations in the RET proto-oncogene.

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13
Q

What endocrine neoplasms are associated with

MEN-2A?

A 
Medullary thyroid carcinoma, pheochromocytoma, and
primary hyperparathyroidism (parathyroid adenoma)
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14
Q

How frequently do individuals with MEN-2A develop the various clinical manifestations of this syndrome?

A

About 70 to 95% develop medullary thyroid carcinoma, 50%
develop pheochromocytoma, and 15 to 30% develop
primary hyperparathyroidism.

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15
Q

What is the typical presentation of medullary thyroid carcinoma in individuals with MEN-2A?

A

In patients with MEN-2A, medullary thyroid carcinoma typically presents with a neck mass or neck pain, usually before age 35 years. Other symptoms include diarrhea or gastrointestinal disturbance.

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16
Q

How frequently are cervical lymph node metastases present on presentation of medullary thyroid carcinoma in MEN-2A?

A

Up to 70%

17
Q

What are the clinical findings associated with MEN-2B?

A

Medullary thyroid carcinoma (particularly aggressive form),
pheochromocytoma, mucosal neuromas, marfanoid body habitus, and diffuse ganglioneuromatosis of the gastrointestinal tract. There is no clinically significant involvement
of the parathyroid gland in MEN-2B.

18
Q

Describe the natural history of medullary thyroid cancer in MEN-2B and its recommended treat-
ment.

A

Almost all patients develop an aggressive form of medullary thyroid carcinoma, with a high rate of metastases before age 10 years. Often, patients will even have microscopic
disease present before the first year of life. Prophylactic
total thyroidectomy is recommended as soon as the infant
is able to tolerate surgery, ideally before age one. In the
past, the average life expectancy was 21 year, before when
prophylactic thyroidectomy was recommended.

19
Q

Describe the distinctive facial features of MEN- 2B.

A

Mucosal neuromas on the dorsal surface of the tongue,
palate, or pharynx; prominent “blubbery” lips; submucosal
nodules on the vermillion border of the lips; and eyelid
neuromas.

20
Q

Describe the distinctive body habitus associated

with MEN-2B.

A

Around 75% of individuals with MEN-2B have a marfanoid
body habitus: tall and lanky, kyphoscoliosis or lordosis, joint
laxity, and proximal muscle wasting.

21
Q

What is the incidence of pheochromocytoma in

MEN-2B?

A

50%; approximately half are bilateral.

22
Q

What defines the clinical diagnosis of familial medullary thyroid carcinoma?

A

Historically, it is diagnosed in families with four or more cases of medullary thyroid carcinoma without pheochromocytomas or parathyroid adenoma or hyperplasia. The RET oncogene is associated with FMTC, so FMTC may be viewed as MEN-2A with reduced organ-specific penetrance.

23
Q

Describe the age of onset and penetrance of medullary thyroid carcinoma in FMTC syndrome compared with MEN-2A and -2B.

A

Medullary thyroid carcinoma has a later age of onset in

FMTC and decreased penetrance compared with MEN-2A and -2B.

24
Q

What is the pattern of inheritance in MEN-2

syndromes?

A

The RET proto-oncogene is inherited in an autosomal
dominant pattern for all MEN-2 syndromes (MEN-2A, -2B,
and FMTC). However, 50% of individuals with MEN-2B have
a de novo germline mutation.

25
Q

What is the recommended primary preventative measure in an individual with an identified germ-line RET mutation?

A

Prophylactic thyroidectomy

26
Q

What is essential before surgery in any patient
with MEN-2A, MEN-2B, or medullary thyroid
carcinoma?

A

Screening for the presence of a functioning pheochromocytoma. Adrenalectomy should be performed before thyroidectomy in any patient with a pheochromocytoma to
avoid intraoperative hypertensive crisis. Calcium and para-
thyroid levels should also be checked for possible primary hyperparathyroidism.

27
Q

What is the rate of recurrence of medullary thyroid
carcinoma in individuals with MEN-2 who have
undergone total thyroidectomy and cervical lymph
node dissections?

A

Approximately 50%

28
Q

In individuals with MEN-2 who have undergone prophylactic thyroidectomy, what is the recommended screening protocol for medullary thyroid carcinoma?

A

Annual serum calcitonin levels

ENT endocrine disorders (5 decks)

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