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32 Cards in this Set
- Front
- Back
__________ are derived from neural crest cells and are incorporated into the _______ thyroid in a _______ pattern.
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C-Cells derived from NCC
Incorporated into mid-lateral thyroid lobes Non-uniform distribution (MEDULLARY CARCINOMAS have same non-uniform distribution) |
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The majority of medullary carcinomas are _________.
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Sporadic (75-80%)
Familial (20-25%) |
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This type of tumor is well circumscribed and fleshy appearance.
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Medullary Carcinoma
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MEN2A RET mutation results in ________.
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Medullary Thyroid Carcinoma
Pheo PT Familial medullary carcinomas bilateral, multicentric Smaller, bilateral tumors |
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MEN2B RET mutations
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Marfanoid habitus (long limbs, spidery fingers, hyermobility--double jointedness)
Neuromas (tumor of nerve tissue) Lip neuromas, tongue neuromas |
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Familial medullary thyroid carcinomas are considered a variant of __________ because _________.
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MEN2A bc both contains mutations to RET gene exons 10, 11, (13, 14--rare)
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MEN syndromes lead to _______ mutations of the _______ gene and can result in _________.
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MEN Syndromes-->activating mutations of RET gene-->neural proliferation (neuromas)
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Which MEN tumor is most aggressive?
Associated RET gene mutation? Associated lesions? |
MEN2B most aggressive (Exon 16 mutation)
Lesions: Pheochromocytoma Ganglioneuromas Marfanoid habitus |
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Which MEN tumor is least aggressive?
Associated RET gene mutations? Associated lesions? |
FMTC
Exons, 10, 11, 13, 14, 15 No associated lesions. |
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Which MEN syndrome is intermediate in aggression?
Associated RET gene mutations? Associated lesions? |
MEN2A = intermediate aggression
Mutations to excons 10, 11, (13, 14 rare) Lesions: Pheochromocytoma Hyperparathyroidism |
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Congo Red is used to stain for ________.
What would you expect to see in a congo red test for medullary carcinoma? |
Amyloid proteins (apple green biofringence = positive test)
Would expect to see calcitonin (from C Cells) with amyloid deposits. |
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How do familial medullary carcinomas differ from non-familial medullary carcinomas?
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Familial medullary carcinomas are BILATERAL and MULTICENTRIC
Non-familial carcinomas are unilateral |
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Which MEN syndromes exhibit mutations to codon 634? Effect on signaling?
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MEN2A
FMTC Effect: constitutive activation by dimerization WITHOUT ligand |
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Which MEN syndromes exhibit mutations to codon 938? Effect on signaling?
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MEN2B
Altered signal transduction (?) |
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__________ is derived from the IVth pharyngeal pouch.
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Upper parathyroid
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_________ is derived from the IIIrd pharyngeal pouch.
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Lower parathyroids
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Which region of parathyroid is much more variable in location?
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LOWER GLANDS (occasionally found in mediastinum)
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What is parathyromatosis?
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multiple nodules of hyperfunctioning parathyroid tissue scattered through the neck and mediastinum (due to developmental variation or seeding)
CAN MIMIC CARCINOMA |
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How do adult parathyroid glands differ from those of children?
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Adult ones have fat!
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_________ is the most common cause of clinically apparent hypercalcemia.
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Malignancy
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Diagnose:
Loss of bone within the medulla with the formation of multiple “brown” cysts, which contain giant cells and iron-containing histiocytes. |
hypercalcemia
bone can be invaded with fibrous tissue with subsequent loss |
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What are the most common causes of primary hyperparathyroidism?
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Adenoma (75-80%): single gland involvement
Hyperplasia (10-15%) Carcinoma (<5%) |
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Characteristics of parathyroid adenoma.
Discuss cells involved. |
Diffuse growth of chief cells in a single gland; should have rim of non-neoplastic thyroid tissue
Little fat within tumor |
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Characteristics of parathyroid carcinomas.
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Rare
Thick fibrous bands Mitotic activity (MITOSES) CAPSULAR and VASCULAR invasion (need invasion to make definitive diagnosis of carcinoma) |
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Which carcinoma characteristics are not definitive for diagnosis of a carcinoma?
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Thick fibrous bands
Mitotic activity These are often lumped under the category of "atypical adenoma"--behave in benign fashion, need active surveillance NEED INVASION AND/OR METS |
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_____________ can involve all 4 parathyroid glands, usually with variation in extent of involvement.
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Primary PThy hyperplasia
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What is Wermer Syndrome?
Characteristic findings? |
Multiple endocrine neoplasia (MEN) type I - disorder in which one or more of the endocrine glands are overactive or form a tumor.
Tumors of: Parathyroids Pituitary (prolactinomas) Pancreas (gastrinomas, duodenal tumors) Hyperparathyroidism due to hyperplasia in 95% of all cases |
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What mutation is associated with Wermer Syndrome?
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MEN1 mutation (tumor suppressor gene)--menin
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Findings of secondary hyperparathyroidism?
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All 4 glands enlarged (even more than in primary hyperpara)
Fibrosis (diff to distinguish from carcinomas) |
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Ambiguities of hyperplasia vs adenoma
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Hyperplasia: asyncrhonous
Fat present in either Some compression occasionally present in hyperplasia |
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Treatment of primary and tertiary hyperplasia of parathyroid.
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Surgery and autografting (to forearm)
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Causes of hypoparathyroidism.
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Surgically induced (removal of parathyroid)
DiGeorge Autoimmune Regulator Gene Mutation (AIRE) |