Difference between revisions of "An introduction to head and neck pathology"

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==Nasopharyngeal carcinoma==
==Nasopharyngeal carcinoma==
*Abbreviated ''NPC''.
*Abbreviated ''NPC''.
===General===
{{Main|Nasopharyngeal carcinoma}}
*"Nasopharyngeal carcinoma" is the name of an entity - it is not a descriptive term.
*Strong association with [[Epstein-Barr virus]] (EBV).
 
Note:
*A morphologically identical tumour elsewhere is called ''[[lymphoepithelioma-like carcinoma]]''.
 
===Gross===
*Nasopharynx - as the name would suggest.
 
===Microscopic===
Features:<ref name=Ref_Klatt145>{{Ref Klatt|145}}</ref>
*Prominent lymphoid component - '''key feature'''.
*Features of squamous cell carcinoma:
**Cohesive cells with:
***Abundant dense eosinophilic cytoplasm.
***Central nuclei +/- small/indistinct nucleoli.
 
Images:
*[http://en.wikipedia.org/wiki/File:Lymphoepithelioma_met_to_LN_4.jpg Nasopharyngeal carcinoma - in a LN - low mag. (WP)].
*[http://commons.wikimedia.org/wiki/File:Lymphoepithelioma_met_to_LN_6.jpg Nasopharyngeal carcinoma - in a LN - intermed. mag. (WC)].
*[http://en.wikipedia.org/wiki/File:Lymphoepithelioma_met_to_LN_2.jpg Nasopharyngeal carcinoma - in a LN - high mag. (WP)].
 
====Histologic subclassification====
World Health Classification (2005) for NPC:<ref name=Ref_WMSP39>{{Ref WMSP|39}}</ref>
{| class="wikitable"
! Type
! Histology
! Description
! EBV
! Prevalence
! Prognosis
|-
| 1
| keratinizing SCC
| graded poorly-well-diff.
| -ve
| ?
| bad
|-
| 2a
| nonkeratinizing carcinoma, differentiated
| well def. cell borders & tumour nest borders, mimics appearance of [[UCC]]
| +ve
| ?
| good
|-
| 2b
| nonkeratinizing carcinoma, undifferentiated
| sheets/syncytial, vescicular nuclei, prominent nucleoli, pink cytoplasm
| ?
| most common
| ?
|-
| 3
| basaloid SCC
| mimics BCC - see [[basaloid SCC]]
| ?
| least common
| ?
|}
 
How to remember ''KNUB'':
*'''K'''eratinizing, '''N'''on-keratinizing diff., non-keratinizing '''U'''ndiff., '''B'''asaloid SCC.
 
===IHC===
*EBER +ve.
*p16 -ve.<ref name=pmid9546345>{{cite journal |author=Gulley ML, Nicholls JM, Schneider BG, Amin MB, Ro JY, Geradts J |title=Nasopharyngeal carcinomas frequently lack the p16/MTS1 tumor suppressor protein but consistently express the retinoblastoma gene product |journal=Am. J. Pathol. |volume=152 |issue=4 |pages=865–9 |year=1998 |month=April |pmid=9546345 |pmc=1858242 |doi= |url=}}</ref>
 
Notes:
*[[HPV-associated head and neck squamous cell carcinoma]]s are p16 +ve.<ref name=pmid21484924>{{Cite journal  | last1 = Singhi | first1 = AD. | last2 = Califano | first2 = J. | last3 = Westra | first3 = WH. | title = High-risk human papillomavirus in nasopharyngeal carcinoma. | journal = Head Neck | volume = 34 | issue = 2 | pages = 213-8 | month = Feb | year = 2012 | doi = 10.1002/hed.21714 | PMID = 21484924 }}</ref>


==Squamous lesions==
==Squamous lesions==
48,830

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