Difference between revisions of "Vermiform appendix"

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

Revision as of 10:55, 16 March 2015

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:

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VERMIFORM APPENDIX WITHIN NORMAL LIMITS.

Negative appendectomy

General

Gross

See normal vermiform appendix.

Microscopic

See normal vermiform appendix.

Notes:

DDx:

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VERMIFORM APPENDIX, APPENDECTOMY:
- APPENDIX NEGATIVE FOR ACUTE APPENDICITIS AND NEGATIVE FOR ACUTE PERIAPPENDICITIS. 

VERMIFORM APPENDIX, APPENDECTOMY:
- APPENDIX WITH LYMPHOID HYPERPLASIA AND FOCAL MUCOSAL EROSIONS.
- NEGATIVE FOR ACUTE APPENDICITIS.
- NEGATIVE FOR ACUTE PERIAPPENDICITIS.

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

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

General

Most common cause:

  • Yersinia appendicitis.[6]

DDx:[7]

  • Yersinia appendicitis.[6]
    • Yersinia = gram negative rod (red on Gram stain).
    • "Safety pin"-like appearance[8] - 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.[9]

Microscopic

Features:

  • Granulomas.
  • +/-"Safety pin"-like organisms (Yersinia).

Image(s):

  • Granulomatous Appendicitis (SKB)

  • Granulomatous Appendicitis (SKB)

  • Granulomatous Suppurating Yersinia Appendicitis (SKB)

Inflammatory bowel disease

See Inflammatory bowel disease.

Periappendicitis

General

Definition: inflammation of tissues around the (vermiform) appendix.[10]

  • 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.[11][12]

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 carcinoid

Main article: Crypt cell carcinoma

Neuroendocrine tumour of the appendix

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

General

  • Most common tumour of the appendix.[13]
    • Not really common though - one is seen in approximately 300 appendectomies.[14]

Size matters in appendiceal NETs:[15]

  • <1.0 cm - do not metastasize.
  • 1.0-2.0 cm - rarely metastasize.

Gross

  • Classically found in the tip of the appendix.

Image:

  • Appendiceal neuroendocrine tumour. (WC)

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:

Images

www:

IHC

Features:

  • Chromogranin A -ve/+ve.
  • Synaptophysin +ve.

See: neuroendocrine tumours.

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. ↑ 6.0 6.1 Lamps LW, Madhusudhan KT, Greenson JK, et al. (April 2001). "The role of Yersinia enterocolitica and Yersinia pseudotuberculosis in granulomatous appendicitis: a histologic and molecular study". Am. J. Surg. Pathol. 25 (4): 508–15. PMID 11257626.
  7. ↑ http://granuloma.homestead.com/appendicitis.html
  8. ↑ URL: http://www.cdc.gov/ncidod/dvbid/plague/p1.htm. Accessed on: 30 June 2011.
  9. ↑ Guo, G.; Greenson, JK. (Aug 2003). "Histopathology of interval (delayed) appendectomy specimens: strong association with granulomatous and xanthogranulomatous appendicitis.". Am J Surg Pathol 27 (8): 1147-51. PMID 12883248.
  10. ↑ URL: http://www.medilexicon.com/medicaldictionary.php?t=66889. Accessed on: 1 June 2011.
  11. ↑ 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.
  12. ↑ O'Neil, MB.; Moore, DB. (Sep 1977). "Periappendicitis: Clinical reality or pathologic curiosity?". Am J Surg 134 (3): 356-7. PMID 900337.
  13. ↑ Mitchell, Richard; Kumar, Vinay; Fausto, Nelson; Abbas, Abul K.; Aster, Jon (2011). Pocket Companion to Robbins & Cotran Pathologic Basis of Disease (8th ed.). Elsevier Saunders. pp. 435. ISBN 978-1416054542.
  14. ↑ Mitra, B.; Pal, M.; Paul, B.; Saha, TN.; Maiti, A. (2013). "Goblet cell carcinoid of appendix: A rare case with literature review.". Int J Surg Case Rep 4 (3): 334-7. doi:10.1016/j.ijscr.2013.01.007. PMID 23416502.
  15. ↑ Modlin, IM.; Lye, KD.; Kidd, M. (Feb 2003). "A 5-decade analysis of 13,715 carcinoid tumors.". Cancer 97 (4): 934-59. doi:10.1002/cncr.11105. PMID 12569593.
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