MEN 2
Epidemiology
and Etiology:
- Autosomal dominant inheritance
- Activating germline mutations of RET gene
(>95%)
- Transmembrane receptor tyrosine kinase
- MEN 2A mutations lead to constitive
dimerization and activation of RET signaling
Common
sites:
- Endocrine:
- Thyroid
- Medullary thyroid carcinoma (MTC)
- Adrenal & autonomic nervous system:
- Adrenal medullary
hyperplasia
- Pheochromocytoma
/ paraganglioma
- Parathyroids
- Non-endocrine:
- Intestine
- Mucoas
- Cornea
- Skeleton
- Skin:
- Cutaneous lichen amyloidosis (some) -
paracrinopathy
- MEN 2A:
- MEN 2B:
- Mucosal neuromas:
- Tongue
- Gangioneuromatosis of the intestine
- Medullated corneal nerve fibres
- Familial MTC:
Gross
features:
- Adrenal pheo:
- Bilateral (mostly)
- Multicentric (mostly)
Histologic
features:
- Adrenals:
- bilateral diffuse or nodular adrenal medullary
hyperplasia (
Immunophenotype:
Marker:
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Sensitivity:
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Specificity:
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Molecular
features:
Other
features:
- prophylactic thyroidectomy is recommended
(<6y for MEN 2A, <6mo for MEN 2B)
- Yearly imaging & urine for pheo at age 6y
- Annual PTH and calcium levels for screening for
hyperparathyroidism
- Remove all parathyroids and thymus when
hyperparathyroidism is diagnosed
- Pulvarize half of one parathyroid and implant
in muscle of arm or neck
References:
- WHO Tumours of Endocrine Organs (2004)