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Difference between revisions of "Parathyroid glands"
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The '''parathyroid glands''' are an endocrine organ that is important in calcium regulation. They often make an appearance in the context of [[thyroid surgery]]. | The '''parathyroid glands''' are an endocrine organ that is important in calcium regulation. They often make an appearance in the context of [[thyroid surgery]]. | ||
==Normal | =Clinical= | ||
==Overview - hyperparathyroidism== | |||
Classification: | |||
*Primary.<ref name=Ref_PBoD8_1127>{{Ref PBoD8|1127}}</ref> | |||
**~90% parathyroid adenoma, ~10% parathyroid hyperplasia, ~1% parathyroid carcinoma. | |||
*Secondary. | |||
*Tertiary. | |||
Familial causes of primary hyperparathyroidism: | |||
*[[MEN 1]]. | |||
*[[MEN 2]]. | |||
*Familial hypocalciuric hypercalcemia. | |||
**Autosomal dominant. | |||
**CASR (calcium sensing receptor) gene defect.<ref name=omim601199>{{OMIM|601199}}</ref> | |||
==Hypercalcemia DDx== | |||
Mnemonic ''GRIMED'':<ref>TN06 Emerg.</ref> | |||
*Granulomatous disease (tuberculosis, [[sarcoidosis]]). | |||
*Renal disease. | |||
*Immobility. | |||
*Malignancy (esp. squamous cell carcinoma, [[plasmacytoma]]). | |||
*Endocrine (primary hyperparathyroidism - leads to brown cell tumour). | |||
*Drugs (thiazides ... others). | |||
=Normal parathyroid glands= | |||
===General=== | ===General=== | ||
*Identification of normal can be tricky. | *Identification of normal can be tricky. | ||
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*[http://pathology.mc.duke.edu/research/PTH225.html Histology - several images. - pathology.mc.duke.edu]. | *[http://pathology.mc.duke.edu/research/PTH225.html Histology - several images. - pathology.mc.duke.edu]. | ||
=Specific entities= | |||
==Parathyroid hyperplasia== | ==Parathyroid hyperplasia== | ||
===General=== | |||
*Chief cell hyperplasia - associated with MEN 1, MEN 2A.<ref>URL: [http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970475-2 http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970475-2]. Accessed on: 29 July 2010.</ref> | |||
*Parathyroid hyperplasia - classically assoc. with renal failure. | *Parathyroid hyperplasia - classically assoc. with renal failure. | ||
* | |||
*Classically all parathyroid glands are involved; however, some may be spared making it difficult to differentiate this from parathyroid adenoma.<ref name=Ref_PBoD8_1128>{{Ref PBoD8|1128}}</ref> | |||
===Microscopic=== | |||
Features:<ref name=Ref_PBoD8_1128>{{Ref PBoD8|1128}}</ref> | |||
*Similar to parathyroid adenoma. | |||
*+/-Water-clear cells ("water-clear cell hyperplasia"). | |||
==Parathyroid adenoma== | ==Parathyroid adenoma== | ||
===General=== | |||
*One parathyroid is big... the others are small. | *One parathyroid is big... the others are small. | ||
*Associated with [[MEN I]] and [[MEN]] IIa/b (II/III). | *Associated with [[MEN I]] and [[MEN]] IIa/b (II/III). | ||
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Image: [http://library.med.utah.edu/WebPath/jpeg4/ENDO091.jpg Parathyroid adenoma (med.utah.edu)].<ref>URL: [http://library.med.utah.edu/WebPath/EXAM/IMGQUIZ/enfrm.html http://library.med.utah.edu/WebPath/EXAM/IMGQUIZ/enfrm.html]. Accessed on: 6 December 2010.</ref> | Image: [http://library.med.utah.edu/WebPath/jpeg4/ENDO091.jpg Parathyroid adenoma (med.utah.edu)].<ref>URL: [http://library.med.utah.edu/WebPath/EXAM/IMGQUIZ/enfrm.html http://library.med.utah.edu/WebPath/EXAM/IMGQUIZ/enfrm.html]. Accessed on: 6 December 2010.</ref> | ||
===Microscopic=== | |||
====Chief cell adenoma==== | |||
Features:<ref name=Ref_PBoD8_1127>{{Ref PBoD8|1127}}</ref> | |||
*Chief cells: | |||
**Small central nucleus. | |||
**Moderate cytoplasm. | |||
*+/-Scattered oxyphil cells: | |||
**Large cells. | |||
**Abundant cytoplasm. | |||
====Oxyphil adenoma==== | |||
Features:<ref name=Ref_PBoD8_1127>{{Ref PBoD8|1127}}</ref> | |||
*Oxyphil cells: | |||
**Large cells. | |||
**Abundant cytoplasm. | |||
DDx: | |||
*[[Hürthle cell adenoma]] of the [[thyroid gland]]. | |||
==Parathyroid carcinoma== | ==Parathyroid carcinoma== | ||
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*Extremely rare. | *Extremely rare. | ||
==See also | ===Microscopic=== | ||
Features:<ref>{{Ref PBoD8|1128}}</ref> | |||
*Histologically normal parathyroid cells. | |||
**Cytologic features not reliable for diagnosis. | |||
*Fibrous capsule. | |||
*Invasion of surrounding tissue - '''key feature'''. | |||
*+/-Metastasis - '''diagnostic feature'''. | |||
Note: | |||
*Diagnosis of ''parathyroid carcinoma'' is like that of ''malignant [[pheochromocytoma]]'' - cytology useless, tissue invasion and metastases are the key features. | |||
Image: | |||
*[http://emedicine.medscape.com/article/280908-overview Parathyroid carcinoma (medscape.com)]. | |||
=See also= | |||
*[[Thyroid gland]]. | *[[Thyroid gland]]. | ||
=References= | |||
{{Reflist|2}} | {{Reflist|2}} | ||
[[Category: Endocrine pathology]] | [[Category: Endocrine pathology]] | ||