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=
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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):
<gallery>
Image:Appendix Appendicitis Acute Granulomatous 2 PA.JPG|Granulomatous Appendicitis (SKB)
Image:Appendix Appendicitis Acute Granulomatous PA.JPG|Suppurating Granulomatous Appendicitis (SKB)
Image:Appendix Appendicitis GranulomatousSuppurating Yersinia-LP PA.JPG|Suppurating Granulomatous Yersinia Appendicitis (SKB)
Image:Appendix Appendicitis GranulomatousSuppurating Yersinia-HP PA.JPG|Suppurating Granulomatous Yersinia Appendicitis  Yersinia(SKB)
</gallery>
*[http://www.cdc.gov/ncidod/dvbid/plague/p1.htm Yersinia (CDC)].


==Inflammatory bowel disease==
==Inflammatory bowel disease==
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This grouping includes ''mucinous cystadenoma'' and ''mucinous cystadenocarcinoma''.
This grouping includes ''mucinous cystadenoma'' and ''mucinous cystadenocarcinoma''.


==Goblet cell carcinoid==
==Goblet cell adenocarcinoma==
{{Main|Crypt cell carcinoma}}
{{Main|Goblet cell adenocarcinoma}}
*Previously known as ''goblet cell carcinoid''.


==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>
===Presentation===
** Often found incidentally, may be microscopic. 
** May cause obstruction leading to mucocele or acute appendicitis.
** May precipitate torsion.
 
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.
*Characteristic yellow cut surface (when fixed)
*Circumscribed but not encapsulated
*Firm (due to desmoplasia)
*Centred in the submucosa
*Nodules that do not usually cause erosion of the overlying mucosa.
 
 
Image:
<gallery>
Image:Appendiceal_carcinoid_1.JPG | Appendiceal neuroendocrine tumour. (WC)
</gallery>
 
===Microscopic===
Features:
*Classically subepithelial/mural.
*Various growth patterns:
**Nested (insular)
**Trabecular
**Palisading
**Ribbons, rosettes
*Fibrous stroma in between cell groups.
*Cytomorphology
**Monotonous appearance with scanty mitoses.
**Round central nuclei
**Stippled chromatin [[AKA]] salt-and-pepper chromatin, coarse chromatin.
**Eosinophilic granular cytoplasm
 
===Special Types===
*Tubular carcinoid
**Neuroendocrine cells forming tubules (no cell nests)
**Some tubules can contain mucin
**Can be confused with adenocarcinoma
**Features suggesting tubular carcinoid (over adenocarcinoma):
***Arises from base of crypts, with no disruption of surface epithelium.
***No associated epithelial precursor (no adenomatous change).
***Neuroendocrine cytologic features, without prominent atypia
***IHC (NE markers +ve)
 
*Goblet cell carcinoid aka [[Crypt cell carcinoma]]
*Signet-ring cells forming glandular structures,
*Possibly also with extra-cellular mucin
 
DDx:
*[[Colorectal adenocarcinoma]].
*Adenocarcinoid.
*[[Crypt cell carcinoma]] (goblet cell carcinoid).
*Metastatic adenocarcinoma.
*Normal ganglion cells in the Meissner plexus (submucosa) and Auerbach plexus (located between the inner and outer layers of the muscularis propria).
 
====Images====
<gallery>
Image: Appendix Carcinoid Torsion 1X PA.JPG|Appendiceal carcinoid with torsion of the appendix - 1x (SKB)
Image: Appendix Carcinoid Torsion LP PA.JPG|Appendiceal carcinoid with torsion of the appendix - low power (SKB)
Image: Appendix Carcinoid Torsion MP PA.JPG|Appendiceal carcinoid with torsion of the appendix - medium power (SKB)
Image: Appendix Carcinoid LP 14BR***.jpg|Appendiceal carcinoid - low power (SKB)
Image: Appendix Carcinoid HP 14BR***.jpg|Appendiceal carcinoid  - high power (SKB)
Image: Appendix Carcinoid Synaptophysin 14BR17120.jpg|Appendiceal carcinoid -  synaptophysin (SKB)
Image: Appendix Carcinoid LP CTR.jpg|Appendiceal carcinoid  - low power (SKB)
Image: Appendix Carcinoid HP CTR.jpg|Appendiceal carcinoid - high power (SKB)
Image: Appendix Carcinoid LP PA.JPG|Appendiceal carcinoid - low power (SKB)
Image: Appendix Carcinoid Necrosis PA.JPG|Appendiceal carcinoid with necrosis (SKB)
</gallery>
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.
*Keratin positive, but CK7/CK20 negative
*S100 positive for appendix
 
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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