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{{ Infobox external links | |||
| Name = Mucinous tumours of the appendix | |||
| EHVSC = 10183 | |||
| pathprotocols = | |||
| wikipedia = | |||
| pathoutlines = | |||
}} | |||
'''Mucinous tumours of the appendix''' are uncommon tumours of the [[vermiform appendix]] that can have a benign or [[malignant]] behaviour. | |||
'''Benign appendiceal [[mucocele]]''' and '''appendiceal mucocele''' redirect here. | |||
==General== | |||
*There are many classifications and they are controversial.<ref name=pmid21970481>{{Cite journal | last1 = Panarelli | first1 = NC. | last2 = Yantiss | first2 = RK. | title = Mucinous neoplasms of the appendix and peritoneum. | journal = Arch Pathol Lab Med | volume = 135 | issue = 10 | pages = 1261-8 | month = Oct | year = 2011 | doi = 10.5858/arpa.2011-0034-RA | PMID = 21970481 }}</ref> | |||
**The controversy centres on whether to call all mucinous tumours outside of the appendix ''adenocarcinoma'' - regardless of whether they have atypia & show invasion. | |||
*''Panarelli and Yantiss'' created a nice summary table - that compare the classifications - see: [http://www.archivesofpathology.org/action/showFullPopup?id=i1543-2165-135-10-1261-t01&doi=10.5858%2Farpa.2011-0034-RA comparison of classifications (archivesofpathology.org)].<ref name=pmid21970481/> | |||
*In women - an ovarian primary must be excluded. | |||
**Concurrent ''bilateral'' ovarian tumours suggests the tumour originated from the appendix and spread to the ovaries. | |||
*[[Onlinepathology]] prefers the classification of Misdraji,<ref name=pmid12883241>{{cite journal |author=Misdraji J, Yantiss RK, Graeme-Cook FM, Balis UJ, Young RH |title=Appendiceal mucinous neoplasms: a clinicopathologic analysis of 107 cases |journal=Am. J. Surg. Pathol. |volume=27 |issue=8 |pages=1089–103 |year=2003 |month=August |pmid=12883241 |doi= |url=http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0147-5185&volume=27&issue=8&spage=1089}}</ref> as it is the least complicated | |||
===Misdraji classification=== | |||
*Benign - ''low grade mucinous tumour''. | |||
*Borderline - ''mucinous tumour of uncertain malignant potential'' or ''borderline mucinous tumour''. | |||
*Malignant - ''[[mucinous adenocarcinoma]]''. | |||
Five year survival (in a series of 107 cases) as per Misdraji classification:<ref name=pmid12883241/> | |||
{| class="wikitable sortable" | |||
!Tumour | |||
!Five year survival | |||
|- | |||
|LAMN | |||
|100% | |||
|- | |||
|LAMN extra-appendiceal spread | |||
|86% | |||
|- | |||
|MACA | |||
|44% | |||
|- | |||
|} | |||
*LAMN = low-grade appendiceal mucinous neoplasm. | |||
*LAMN extra-appendiceal = low-grade appendiceal mucinous neoplasm with extra-appendiceal spread. | |||
*MACA = mucinous adenocarcinoma of the appendix. | |||
===World Health Organization classification=== | |||
WHO classification: | |||
*Adenoma with low-grade dysplasia. | |||
*Adenoma with high-grade dysplasia. | |||
*Low-grade invasive mucinous adenocarcinoma | |||
**Confined to the appendiceal wall. | |||
**Outside of the appendix. | |||
*High-grade invasive mucinous adenocarcinoma. | |||
===Comparison between Misdraji and WHO classification=== | |||
Adapted from ''Panarelli and Yantiss'':<ref name=pmid21970481>{{Cite journal | last1 = Panarelli | first1 = NC. | last2 = Yantiss | first2 = RK. | title = Mucinous neoplasms of the appendix and peritoneum. | journal = Arch Pathol Lab Med | volume = 135 | issue = 10 | pages = 1261-8 | month = Oct | year = 2011 | doi = 10.5858/arpa.2011-0034-RA | PMID = 21970481 }}</ref> | |||
{| class="wikitable sortable" | |||
! Stage | |||
! Cytologic dysplasia | |||
! Misdraji | |||
! World Health Organization | |||
|- | |||
| Confined to the mucosa | |||
| low-grade | |||
| low-grade appendiceal mucinous neoplasm (LAMN) | |||
| mucinous adenoma, negative for high-grade dysplasia | |||
|- | |||
| Confined to the mucosa | |||
| high-grade | |||
| non-invasive mucinous cystadenocarcinoma of the appendix | |||
| mucinous adenoma with high-grade dysplasia | |||
|- | |||
| At least into the submucosa, confined to the appendix | |||
| low-grade | |||
| low-grade appendiceal mucinous neoplasm (LAMN) | |||
| invasive mucinous adenocarcinoma, low-grade | |||
|- | |||
| At least into the submucosa, confined to the appendix | |||
| high-grade | |||
| mucinous adenocarcinoma of the appendix (MACA) | |||
| invasive mucinous adenocarcinoma, high-grade | |||
|- | |||
| Extra-appendiceal spread | |||
| low-grade | |||
| low-grade appendiceal mucinous neoplasm (LAMN) | |||
| invasive mucinous adenocarcinoma, low-grade | |||
|- | |||
| Extra-appendiceal spread | |||
| high-grade | |||
| mucinous adenocarcinoma of the appendix (MACA) | |||
| invasive mucinous adenocarcinoma, high-grade | |||
|} | |||
==Microscopic== | |||
===Low-grade appendiceal mucinous neoplasm=== | |||
*[[AKA]] ''benign mucinous tumour of the appendix''. | |||
Microscopic: | |||
*Single layer of epithelium with ''tufts''. | |||
**Vaguely resemble ''serrations'', i.e. the ''saw-tooth'' pattern in hyperplastic polyps of the colon. | |||
*Mucin contained (inside appendix only). | |||
*No marked nuclear atypia. | |||
Note: | |||
*May be deceptively bland appearing from a cytologic perspective. | |||
Images: | |||
*[http://www.nature.com/modpathol/journal/v17/n12/fig_tab/3800212f1.html LAMN - low mag. (nature.com)].<ref name=pmid15354187/> | |||
*[http://www.nature.com/modpathol/journal/v17/n12/fig_tab/3800212f3.html LAMN - high mag. (nature.com)].<ref name=pmid15354187>{{Cite journal | last1 = Misdraji | first1 = J. | last2 = Burgart | first2 = LJ. | last3 = Lauwers | first3 = GY. | title = Defective mismatch repair in the pathogenesis of low-grade appendiceal mucinous neoplasms and adenocarcinomas. | journal = Mod Pathol | volume = 17 | issue = 12 | pages = 1447-54 | month = Dec | year = 2004 | doi = 10.1038/modpathol.3800212 | PMID = 15354187 }}</ref> | |||
*[http://pathlabmed.typepad.com/surgical_pathology_and_la/2012/02/digital-case-simple-mucocele-of-the-appendix.html Appendiceal mucocele (pathlabmed.typepad.com)]. | |||
===Low-grade appendiceal mucinous neoplasm with extra-appendiceal spread=== | |||
*[[AKA]] ''mucinous borderline tumour of the appendix''. | |||
Microscopic: | |||
*Same as LAMN but mucin outside of the appendix. | |||
*Cells in mucin, i.e. cellular mucin. | |||
===Mucinous adenocarcinoma of the appendix=== | |||
*[[AKA]] ''malignant mucinous tumour of the appendix''. | |||
Microscopic: | |||
*Marked nuclear pleomorphism. | |||
*Invasion into the appendiceal wall. | |||
==Sign out== | |||
===LAMN=== | |||
<pre> | |||
VERMIFORM APPENDIX, APPENDECTOMY: | |||
- LOW-GRADE APPENDICEAL MUCINOUS NEOPLASM. | |||
- ACUTE APPENDICITIS. | |||
- ACUTE PERIAPPENDICITIS. | |||
</pre> | |||
<pre> | |||
VERMIFORM APPENDIX AND CECUM, APPENDECTOMY WITH CECAL CUFF: | |||
- LOW-GRADE APPENDICEAL MUCINOUS NEOPLASM (MUCINOUS CYSTADENOMA). | |||
- MARGINS NEGATIVE FOR MUCINOUS NEOPLASM. | |||
COMMENT: | |||
No extra-appendiceal mucin is identified. There is no invasion into the appendiceal wall. | |||
</pre> | |||
<pre> | |||
APPENDIX, APPENDECTOMY: | |||
- APPENDICEAL MUCINOUS CYSTADENOMA WITH EXTENSIVE CALCIFICATION. | |||
-- NEGATIVE FOR HIGH-GRADE DYSPLASIA. | |||
- NEGATIVE FOR MALIGNANCY. | |||
</pre> | |||
==See also== | |||
*[[Vermiform appendix]]. | |||
*[[Mucinous carcinoma]]. | |||
==References== | |||
{{Reflist|2}} | |||
[[Category:Vermiform appendix]] |
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