Difference between revisions of "Vermiform appendix"

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VERMIFORM APPENDIX WITHIN NORMAL LIMITS.
VERMIFORM APPENDIX WITHIN NORMAL LIMITS.
</pre>
</pre>
Note:
*This is for a normal appendix within a larger operation. The article ''[[negative appendectomy]]'' deals with a normal appearing appendix that was removed for presumed appendicitis.


==Negative appendectomy==
==Negative appendectomy==
===General===
{{Main|Negative appendectomy}}
*Common.
An appendectomy done for presumed [[acute appendicitis]] that is pathologically within normal limits
*Use for quality control among general surgeons.{{fact}}
 
===Gross===
See ''[[normal vermiform appendix]]''.
 
===Microscopic===
See ''[[normal vermiform appendix]]''.
 
Notes:
*Should be ''[[submitted in total]]''.
 
DDx:
*[[Acute appendicitis]].
*[[Adenovirus appendicitis]].
*[[Appendiceal neuroendocrine tumour]].
*Non-appendiceal pathology - see DDx of ''[[acute appendicitis]].
**Isolated [[periappendicitis]].
 
===Sign out===
<pre>
VERMIFORM APPENDIX, APPENDECTOMY:
- APPENDIX NEGATIVE FOR ACUTE APPENDICITIS AND NEGATIVE FOR ACUTE PERIAPPENDICITIS.
</pre>
 
<pre>
VERMIFORM APPENDIX, APPENDECTOMY:
- APPENDIX WITH LYMPHOID HYPERPLASIA AND FOCAL MUCOSAL EROSIONS.
- NEGATIVE FOR ACUTE APPENDICITIS.
- NEGATIVE FOR ACUTE PERIAPPENDICITIS.
</pre>
 
====Micro====
The sections show appendiceal wall with focal mucosa erosions and several intraluminal
neutrophil clusters.  Lymphoid hyperplasia is present. Fecal material is present within
the lumen of the appendix.
 
There are no neutrophils within the muscularis propria. There is no serositis. There is
no distortion of the crypt architecture. No granulomas are identified. No cryptitis is
identified.


=Inflammatory pathologies=
=Inflammatory pathologies=
Line 90: Line 54:


==Adenovirus appendicitis==
==Adenovirus appendicitis==
===General===
{{Main|Adenovirus appendicitis}}
*Rare type of appendicitis in children.
*Presents as run-of-the-mill acute appendicitis.
*Caused by ''[[Adenovirus]]''.
 
===Microscopic===
Features:<ref name=pmid17990936>{{cite journal |author=Grynspan D, Rabah R |title=Adenoviral appendicitis presenting clinically as acute appendicitis |journal=Pediatr. Dev. Pathol. |volume=11 |issue=2 |pages=138–41 |year=2008 |pmid=17990936 |doi=10.2350/07-06-0299.1 |url=}}</ref>
*Lymphoid hyperplasia - key feature.
*+/-Adenovirus inclusions; "smudge cells".
 
Notes:
*The classic finding of appendicitis (neutrophils infiltrating into the muscularis propria) may be absent.<ref name=pmid17990936/>
 
Image:
*[http://wiki.medpedia.com/Image:Ab14.jpg?filetimestamp=20091014175858 Smudge cell (medpedia.com)].
 
===IHC===
*Adenovirus +ve = '''diagnostic'''.


==Enterobius vermicularis==
==Enterobius vermicularis==
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==Granulomatous appendicitis==
==Granulomatous appendicitis==
===General===
{{Main|Granulomatous appendicitis}}
Most common cause:
*Yersinia appendicitis.<ref name=pmid11257626>{{cite journal |author=Lamps LW, Madhusudhan KT, Greenson JK, ''et al.'' |title=The role of Yersinia enterocolitica and Yersinia pseudotuberculosis in granulomatous appendicitis: a histologic and molecular study |journal=Am. J. Surg. Pathol. |volume=25 |issue=4 |pages=508–15 |year=2001 |month=April |pmid=11257626 |doi= |url=}}</ref>
 
DDx:<ref>[http://granuloma.homestead.com/appendicitis.html http://granuloma.homestead.com/appendicitis.html]</ref>
*Yersinia appendicitis.<ref name=pmid11257626>{{cite journal |author=Lamps LW, Madhusudhan KT, Greenson JK, ''et al.'' |title=The role of Yersinia enterocolitica and Yersinia pseudotuberculosis in granulomatous appendicitis: a histologic and molecular study |journal=Am. J. Surg. Pathol. |volume=25 |issue=4 |pages=508–15 |year=2001 |month=April |pmid=11257626 |doi= |url=}}</ref>
**Yersinia = gram negative rod (red on [[Gram stain]]).
**"Safety pin"-like appearance<ref>URL: [http://www.cdc.gov/ncidod/dvbid/plague/p1.htm http://www.cdc.gov/ncidod/dvbid/plague/p1.htm]. Accessed on: 30 June 2011.</ref> - approximately 0.5 micrometers diameter x 2 micrometers length.
*Other micro-organism ([[TB]], fungus).
*[[Crohn's disease]].
*[[Sarcoidosis]].
*Foreign body reaction.
*Interval (delayed) appendectomy.
**Approximately 60% of delayed appendectomies have granulomas.<ref name=pmid12883248>{{Cite journal  | last1 = Guo | first1 = G. | last2 = Greenson | first2 = JK. | title = Histopathology of interval (delayed) appendectomy specimens: strong association with granulomatous and xanthogranulomatous appendicitis. | journal = Am J Surg Pathol | volume = 27 | issue = 8 | pages = 1147-51 | month = Aug | year = 2003 | doi =  | PMID = 12883248 }}</ref>
 
===Microscopic===
Features:
*[[Granulomas]].
*+/-"Safety pin"-like organisms (Yersinia).
 
Image(s):
*[http://www.cdc.gov/ncidod/dvbid/plague/p1.htm Yersinia (CDC)].


==Inflammatory bowel disease==
==Inflammatory bowel disease==
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==Mucinous tumours of the appendix==
==Mucinous tumours of the appendix==
{{ Infobox external links
{{Main|Mucinous tumours of the appendix}}
| Name          = Mucinous tumours of the appendix
This grouping includes ''mucinous cystadenoma'' and ''mucinous cystadenocarcinoma''.
| EHVSC          = 10183
| pathprotocols  =
| wikipedia      =
| pathoutlines  =
}}
:''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====
==Goblet cell adenocarcinoma==
*Benign - ''low grade mucinous tumour''.
{{Main|Goblet cell adenocarcinoma}}
*Borderline - ''mucinous tumour of uncertain malignant potential'' or ''borderline mucinous tumour''.
*Previously known as ''goblet cell carcinoid''.
*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>
 
==Goblet cell carcinoid==
{{Main|Crypt cell carcinoma}}


==Neuroendocrine tumour of the appendix==
==Neuroendocrine tumour of the appendix==
{{Main|Neuroendocrine tumour}}
*Previously known as ''appendiceal carcinoid''.
*Previously known as ''appendiceal carcinoid''.
*[[AKA]] ''appendiceal neuroendocrine tumour'', abbreviated ''appendiceal NET''.  
*[[AKA]] ''appendiceal neuroendocrine tumour'', abbreviated ''appendiceal NET''.  
===General===
{{Main|Neuroendocrine tumour of the appendix}}
*Most common tumour of the appendix.<ref name=PCPBoD8_435>{{Ref PCPBoD8|435}}</ref>
**Not really common though - one is seen in approximately 300 appendectomies.<ref name=pmid23416502>{{Cite journal  | last1 = Mitra | first1 = B. | last2 = Pal | first2 = M. | last3 = Paul | first3 = B. | last4 = Saha | first4 = TN. | last5 = Maiti | first5 = A. | title = Goblet cell carcinoid of appendix: A rare case with literature review. | journal = Int J Surg Case Rep | volume = 4 | issue = 3 | pages = 334-7 | month =  | year = 2013 | doi = 10.1016/j.ijscr.2013.01.007 | PMID = 23416502 }}</ref>
 
Size matters in ''appendiceal NETs'':<ref name=pmid12569593>{{Cite journal  | last1 = Modlin | first1 = IM. | last2 = Lye | first2 = KD. | last3 = Kidd | first3 = M. | title = A 5-decade analysis of 13,715 carcinoid tumors. | journal = Cancer | volume = 97 | issue = 4 | pages = 934-59 | month = Feb | year = 2003 | doi = 10.1002/cncr.11105 | PMID = 12569593 }}</ref>
*<1.0 cm - do not metastasize.
*1.0-2.0 cm - rarely metastasize.
 
===Gross===
*Classically found in the tip of the appendix.
 
Image:
<gallery>
Image:Appendiceal_carcinoid_1.JPG | Appendiceal neuroendocrine tumour. (WC)
</gallery>
 
===Microscopic===
Features:
*Nests of cells - with fibrous stroma in between.
**May have a trabecular architecture.
*Stippled chromatin [[AKA]] salt-and-pepper chromatin, coarse chromatin.
*Classically subepithelial/mural.
 
DDx:
*[[Colorectal adenocarcinoma]].
*[[Crypt cell carcinoma]] (goblet cell carcinoid).
*Metastatic adenocarcinoma.
 
====Images=====
www:
*[http://www.humpath.com/spip.php?article10881&id_document=19109#documents_portfolio Appendiceal carcinoid (humpath.com)].
*[http://www.brown.edu/Courses/Digital_Path/systemic_path/GI/AppendicealCarcinoid.html Carcinoid of the appendix (brown.edu)].
*[http://www.flickr.com/photos/jian-hua_qiao_md/8494061964/in/photostream/ Appendiceal carcinoid (flickr.com/Qiao)].
 
===IHC===
Features:
*Chromogranin A -ve/+ve.
*Synaptophysin +ve.
 
See: ''[[neuroendocrine tumours]]''.


=See also=
=See also=

Latest revision as of 15:11, 4 December 2023

The vermiform appendix, usually just appendix, is a little thingy that is attached to the cecum. Taking it out is the bread 'n butter of general surgery.

The appendix is a vestigial structure that is thought to have arisen from a larger cecum. Larger cecae are often seen in herbivores and thought to facilitate better digestion of plant matter.[1]

Normal

Normal vermiform appendix

General

Gross

  • Shiny serosal surface.
    • No exudate.
  • Normal diameter.
    • 6.6 +/- 1.5 mm -- based on CT.[2]

Microscopic

Features:

  • +/-Lymphoid hyperplasia - mucosa or submucosa.
  • Normal colorectal-type mucosa.
  • Fatty submucosa.
  • Benign smooth muscle.
  • Serosa.

Negatives:

DDx:

Sign out

VERMIFORM APPENDIX WITHIN NORMAL LIMITS.

Note:

  • This is for a normal appendix within a larger operation. The article negative appendectomy deals with a normal appearing appendix that was removed for presumed appendicitis.

Negative appendectomy

Main article: Negative appendectomy

An appendectomy done for presumed acute appendicitis that is pathologically within normal limits

Inflammatory pathologies

Acute appendicitis

Main article: Acute appendicitis

Adenovirus appendicitis

Main article: Adenovirus appendicitis

Enterobius vermicularis

Main article: Enterobius vermicularis

General

  • May be found in the appendix.
  • The incidence is higher in normal appendices than inflamed ones.[3][4]
  • Clinically mimics appendicitis.[5]

Microscopic

Features:

Image

  • Enterobius - very low mag. (WC/Nephron)

  • Enterobius - high mag. (WC/Nephron)

  • Pinworm (WC/Uthman)

Granulomatous appendicitis

Main article: Granulomatous appendicitis

Inflammatory bowel disease

See Inflammatory bowel disease.

Periappendicitis

General

Definition: inflammation of tissues around the (vermiform) appendix.[6]

  • May be seen in association of appendicitis or alone.
    • With appendicitis it is suggestive of perforation.
    • Without concurrent appendicitis it is suggestive of another abdominal pathology.[7][8]

Microscopic

Features:

  • Acute inflammation of the serosa.

DDx:

Tumours of the appendix

Adenocarcinoma

Mucinous tumours of the appendix

Main article: Mucinous tumours of the appendix

This grouping includes mucinous cystadenoma and mucinous cystadenocarcinoma.

Goblet cell adenocarcinoma

Main article: Goblet cell adenocarcinoma
  • Previously known as goblet cell carcinoid.

Neuroendocrine tumour of the appendix

  • Previously known as appendiceal carcinoid.
  • AKA appendiceal neuroendocrine tumour, abbreviated appendiceal NET.
Main article: Neuroendocrine tumour of the appendix

See also

References

  1. ↑ Dawkins, R. (2009). The Greatest Show on Earth: The Evidence for Evolution (1st ed.). Free Press. pp. 115. ISBN 978-1416594789.
  2. ↑ Charoensak, A.; Pongpornsup, S.; Suthikeeree, W. (Dec 2010). "Wall thickness and outer diameter of the normal appendix in adults using 64 slices multidetector CT.". J Med Assoc Thai 93 (12): 1437-42. PMID 21344807.
  3. ↑ 3.0 3.1 Wiebe, BM. (Mar 1991). "Appendicitis and Enterobius vermicularis.". Scand J Gastroenterol 26 (3): 336-8. PMID 1853157.
  4. ↑ 4.0 4.1 Dahlstrom, JE.; Macarthur, EB. (Oct 1994). "Enterobius vermicularis: a possible cause of symptoms resembling appendicitis.". Aust N Z J Surg 64 (10): 692-4. PMID 7945067.
  5. ↑ Ariyarathenam AV, Nachimuthu S, Tang TY, Courtney ED, Harris SA, Harris AM (2010). "Enterobius vermicularis infestation of the appendix and management at the time of laparoscopic appendectomy: case series and literature review". Int J Surg 8 (6): 466–9. doi:10.1016/j.ijsu.2010.06.007. PMID 20637320.
  6. ↑ URL: http://www.medilexicon.com/medicaldictionary.php?t=66889. Accessed on: 1 June 2011.
  7. ↑ Fink, AS.; Kosakowski, CA.; Hiatt, JR.; Cochran, AJ. (Jun 1990). "Periappendicitis is a significant clinical finding.". Am J Surg 159 (6): 564-8. PMID 2349982.
  8. ↑ O'Neil, MB.; Moore, DB. (Sep 1977). "Periappendicitis: Clinical reality or pathologic curiosity?". Am J Surg 134 (3): 356-7. PMID 900337.
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