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.
*Chief cell hyperplasia - associated with MEN I, MEN IIa.<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>
 
*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==
=References=
{{Reflist|2}}
{{Reflist|2}}


[[Category: Endocrine pathology]]
[[Category: Endocrine pathology]]
Retrieved from "https://librepathology.org/wiki/Parathyroid_glands"