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| The '''vermiform appendix''' is, 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 '''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]]. |
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| 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.<ref>{{cite book |author=Dawkins, R. |title=The Greatest Show on Earth: The Evidence for Evolution |publisher=Free Press |location= |year=2009 |pages=115 |edition=1st |isbn=978-1416594789 |oclc= |doi= |accessdate=}}</ref> | | 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.<ref>{{cite book |author=Dawkins, R. |title=The Greatest Show on Earth: The Evidence for Evolution |publisher=Free Press |location= |year=2009 |pages=115 |edition=1st |isbn=978-1416594789 |oclc= |doi= |accessdate=}}</ref> |
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| =Appendicitis= | | =Normal= |
| ==Acute appendicitis== | | ==Normal vermiform appendix== |
| ===General=== | | ===General=== |
| *Bread 'n butter of general surgery. | | *Seen in: |
| *Interesting factoid: appendicitis is considered protective against [[ulcerative colitis]].<ref name=pmid19685454>{{Cite journal | last1 = Beaugerie | first1 = L. | last2 = Sokol | first2 = H. | title = Appendicitis, not appendectomy, is protective against ulcerative colitis, both in the general population and first-degree relatives of patients with IBD. | journal = Inflamm Bowel Dis | volume = | issue = | pages = | month = Aug | year = 2009 | doi = 10.1002/ibd.21064 | PMID = 19685454 }}</ref><ref name=pmid19273505>{{Cite journal | last1 = Timmer | first1 = A. | last2 = Obermeier | first2 = F. | title = Reduced risk of ulcerative colitis after appendicectomy. | journal = BMJ | volume = 338 | issue = | pages = b225 | month = | year = 2009 | doi = | PMID = 19273505 }}</ref> | | **Right hemicolectomies. |
| | ***[[colorectal carcinoma|Colon cancer]]. |
| | ***[[Crohn's disease]]. |
| | **Surgeries for ovarian mucinous tumours. |
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| ===Gross=== | | ===Gross=== |
| Features:
| | *Shiny serosal surface. |
| *Serosal surface dull. | | **No exudate. |
| *May be perforated (best determined on gross). | | *Normal diameter. |
| *+/-Fibrinous exudate. | | **6.6 +/- 1.5 mm -- based on CT.<ref name=pmid21344807>{{Cite journal | last1 = Charoensak | first1 = A. | last2 = Pongpornsup | first2 = S. | last3 = Suthikeeree | first3 = W. | title = Wall thickness and outer diameter of the normal appendix in adults using 64 slices multidetector CT. | journal = J Med Assoc Thai | volume = 93 | issue = 12 | pages = 1437-42 | month = Dec | year = 2010 | doi = | PMID = 21344807 }}</ref> |
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| ===Microscopic=== | | ===Microscopic=== |
| Features: | | Features: |
| * Neutrophils in the muscularis propria - '''key feature'''.
| | *+/-Lymphoid hyperplasia - mucosa or submucosa. |
| * +/- Vascular thrombosis (and [[necrosis]]) - known as ''gangrenous appendicitis''.<ref>URL: [http://emedicine.medscape.com/article/363818-overview http://emedicine.medscape.com/article/363818-overview]. Accessed on: 21 June 2010.</ref> | | *Normal colorectal-type mucosa. |
| * +/- Findings suggestive of etiology - usu. absent: | | *Fatty submucosa. |
| ** +/- Fecalith. | | *Benign smooth muscle. |
| ** +/- Viral inclusions (extremely rare) | | *Serosa. |
| *** See ''[[adenovirus appendicitis]]''. | |
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| ====DDx====
| | Negatives: |
| *Mucinous tumour. | | *No [[neutrophil]]s in the muscularis propria. |
| *Neuroendocrine tumour. | | *No lesion in appendiceal tip. |
| *Granulomatous appendicitis. | | *No serosal inflammation ([[periappendicitis]]). |
| *Crohn's disease of the appendix. | | *No organisms in the appendiceal lumen, e.g. [[Enterobius vermicularis]]. |
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| ==Adenovirus appendicitis==
| | DDx: |
| ===General===
| | *[[Adenovirus appendicitis]]. |
| *Rare type of appendicitis in children. | | *[[Cryptosporidiosis]]. |
| *Presents as run-of-the-mill acute appendicitis. | | *Mild colitis. |
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| ===Microscopic=== | | ===Sign out=== |
| 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>
| | <pre> |
| *Lymphoid hyperplasia - key feature.
| | VERMIFORM APPENDIX WITHIN NORMAL LIMITS. |
| *+/-Adenovirus inclusions; "smudge cells".
| | </pre> |
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| Notes:
| | Note: |
| *The classic finding of appendicitis (neutrophils infiltrating into the muscularis propria) may be absent.<ref name=pmid17990936/> | | *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. |
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| Image:
| | ==Negative appendectomy== |
| *[http://wiki.medpedia.com/Image:Ab14.jpg?filetimestamp=20091014175858 Smudge cell (medpedia.com)].
| | {{Main|Negative appendectomy}} |
| | An appendectomy done for presumed [[acute appendicitis]] that is pathologically within normal limits |
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| ===IHC=== | | =Inflammatory pathologies= |
| *Adenovirus +ve = '''diagnostic'''.
| | ==Acute appendicitis== |
| | {{Main|Acute appendicitis}} |
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| ==Granulomatous appendicitis== | | ==Adenovirus appendicitis== |
| Most common cause:
| | {{Main|Adenovirus appendicitis}} |
| *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>
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| DDx:<ref>[http://granuloma.homestead.com/appendicitis.html http://granuloma.homestead.com/appendicitis.html]</ref>
| | ==Enterobius vermicularis== |
| *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> | | {{Main|Enterobius vermicularis}} |
| **Yersinia = gram negative rod.
| | *[[AKA]] ''pinworm''. |
| *Other micro-organism (TB, fungus).
| | ===General=== |
| *[[Crohn's disease]].
| | *May be found in the appendix. |
| *[[Sarcoidosis]].
| | *The incidence is higher in normal appendices than inflamed ones.<ref name=pmid1853157>{{Cite journal | last1 = Wiebe | first1 = BM. | title = Appendicitis and Enterobius vermicularis. | journal = Scand J Gastroenterol | volume = 26 | issue = 3 | pages = 336-8 | month = Mar | year = 1991 | doi = | PMID = 1853157 }}</ref><ref name=pmid7945067/> |
| *Foreign body reaction.
| | *Clinically mimics appendicitis.<ref>{{cite journal |author=Ariyarathenam AV, Nachimuthu S, Tang TY, Courtney ED, Harris SA, Harris AM |title=Enterobius vermicularis infestation of the appendix and management at the time of laparoscopic appendectomy: case series and literature review |journal=Int J Surg |volume=8 |issue=6 |pages=466–9 |year=2010 |pmid=20637320 |doi=10.1016/j.ijsu.2010.06.007 |url=}}</ref> |
| *Interval (delayed) appendectomy.
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| ===Microscopic=== | | ===Microscopic=== |
| Features: | | Features: |
| *Granulomas. | | *Usu. the appendiceal wall has no inflammation, i.e. there is no appendicitis.<ref name=pmid1853157/><ref name=pmid7945067>{{Cite journal | last1 = Dahlstrom | first1 = JE. | last2 = Macarthur | first2 = EB. | title = Enterobius vermicularis: a possible cause of symptoms resembling appendicitis. | journal = Aust N Z J Surg | volume = 64 | issue = 10 | pages = 692-4 | month = Oct | year = 1994 | doi = | PMID = 7945067 }}</ref> |
| | | *''[[Enterobius vermicularis]]'' organisms. |
| =Tumours of the appendix= | |
| ==Adenocarcinoma== | |
| *Like ''colorectal adenocarcinoma'' - see ''[[colorectal tumours]]''. | |
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| ==Mucinous tumour== | | ====Image==== |
| General
| | <gallery> |
| *classification is controversial.
| | Image:Enterobius_-_very_low_mag.jpg | Enterobius - very low mag. (WC/Nephron) |
| **the controversy centres on whether to call all mucinous tumours outside of the appendix adenocarcinoma - regardless of whether they have atypia & show invasion.
| | Image:Enterobius_-_high_mag.jpg | Enterobius - high mag. (WC/Nephron) |
| *in women - an ovarian primary must be excluded.
| | Image:Pinworms_in_the_Appendix_%281%29.jpg | Pinworm (WC/Uthman) |
| **concurrent ''bilateral'' ovarian tumours suggests the tumour originated from the appendix and spread to the ovaries.
| | </gallery> |
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| Classification<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>
| | ==Granulomatous appendicitis== |
| *benign - ''low grade mucinous tumour''.
| | {{Main|Granulomatous appendicitis}} |
| *borderline - ''mucinous tumour of uncertain malignant potential'' or ''borderline mucinous tumour''.
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| *malignant - ''mucinous adenocarcinoma''.
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| Five year survival<ref name=pmid12883241/>
| | ==Inflammatory bowel disease== |
| {| class="wikitable"
| | : See ''[[Inflammatory bowel disease]]''. |
| | ||'''5 year survival'''
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| |-
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| |LAMN ||100%
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| |LAMN ex-appy ||86%
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| |MACA ||44%
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| |-
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| |}
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| *LAMN = low-grade appendiceal mucinous neoplasm.
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| *LAMN ex-appy = LAMN with extra-appendiceal spread.
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| *MACA = mucinous adenocarcinoma.
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| ===Benign mucinous tumour=== | | ==Periappendicitis== |
| Micro.
| | ===General=== |
| *Epithelium forms ''tufts'' - vaguely resemble ''serrations'', i.e. the ''saw-tooth'' pattern in hyperplastic polyps.
| | Definition: inflammation of tissues around the (vermiform) appendix.<ref>URL: [http://www.medilexicon.com/medicaldictionary.php?t=66889 http://www.medilexicon.com/medicaldictionary.php?t=66889]. Accessed on: 1 June 2011.</ref> |
| *Single layer of epithelium.
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| *Mucin contained (inside appendix only).
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| Negatives
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| *No marked nuclear atypia.
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| *No invasion into the lamina propria.
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| ===Borderline mucinous tumour=== | |
| Micro.
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| *Same as benign, but mucin outside of the appendix.
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| *Cells in mucin, i.e. cellular mucin.
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| ===Malignant mucinous tumour=== | |
| Micro.
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| *Marked nuclear pleomorphism.
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| *Invasion into the wall.
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| ==Goblet cell carcinoid==
| | *May be seen in association of appendicitis or alone. |
| ===General===
| | **With appendicitis it is suggestive of perforation. |
| *[[AKA]] '''crypt cell carcinoma''',<ref name=pmid18042066>{{cite journal |author=van Eeden S, Offerhaus GJ, Hart AA, ''et al.'' |title=Goblet cell carcinoid of the appendix: a specific type of carcinoma |journal=Histopathology |volume=51 |issue=6 |pages=763–73 |year=2007 |month=December |pmid=18042066 |doi=10.1111/j.1365-2559.2007.02883.x |url=}}</ref> '''neuroendocrine tumour with goblet cell differentiation. | | **Without concurrent appendicitis it is suggestive of another abdominal pathology.<ref name=pmid2349982>{{Cite journal | last1 = Fink | first1 = AS. | last2 = Kosakowski | first2 = CA. | last3 = Hiatt | first3 = JR. | last4 = Cochran | first4 = AJ. | title = Periappendicitis is a significant clinical finding. | journal = Am J Surg | volume = 159 | issue = 6 | pages = 564-8 | month = Jun | year = 1990 | doi = | PMID = 2349982 }}</ref><ref>{{Cite journal | last1 = O'Neil | first1 = MB. | last2 = Moore | first2 = DB. | title = Periappendicitis: Clinical reality or pathologic curiosity? | journal = Am J Surg | volume = 134 | issue = 3 | pages = 356-7 | month = Sep | year = 1977 | doi = | PMID = 900337 }}</ref> |
| *Rare appendiceal tumour that typically has an aggressive course vis-a-vis other appendiceal carcinoids.<ref name=pmid18042066>{{cite journal |author=van Eeden S, Offerhaus GJ, Hart AA, ''et al.'' |title=Goblet cell carcinoid of the appendix: a specific type of carcinoma |journal=Histopathology |volume=51 |issue=6 |pages=763–73 |year=2007 |month=December |pmid=18042066 |doi=10.1111/j.1365-2559.2007.02883.x |url=}}</ref>
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| *Mixed (biphasic) tumour with endocrine and exocrine features.
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| ===Microscopic=== | | ===Microscopic=== |
| Features:<ref name=pmid15967038>{{cite journal |author=Pahlavan PS, Kanthan R |title=Goblet cell carcinoid of the appendix |journal=World J Surg Oncol |volume=3 |issue= |pages=36 |year=2005 |month=June |pmid=15967038 |pmc=1182398 |doi=10.1186/1477-7819-3-36 |url=http://wjso.com/content/3/1/36}}</ref> | | Features: |
| *Mixed neuroendocrine-nonneuroendocrine tumour;<ref name=pmid17684764>{{cite journal |author=Volante M, Righi L, Asioli S, Bussolati G, Papotti M |title=Goblet cell carcinoids and other mixed neuroendocrine/nonneuroendocrine neoplasms |journal=Virchows Arch. |volume=451 Suppl 1 |issue= |pages=S61–9 |year=2007 |month=August |pmid=17684764 |doi=10.1007/s00428-007-0447-y |url=}}</ref> features of both ''carcinoid'' and ''adenocarcinoma.<ref name=pmid15967038>PMID 15967038.</ref> | | *Acute inflammation of the serosa. |
| **Archictecture: cells arranged in nests or clusters without a lumen. | | **[[Neutrophil]]s in the serosa. |
| **Location: deep to the intestinal crypts (crypts of Lieberkühn); usually do not involve the mucosa.
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| **Cytoplasm distended with mucin.
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| **DNA: crescentic nucleus (similar to in signet-ring cells).
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| ***+/-Multinucleation.
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| ***+/-High mitotic rate.
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| ***Usually minimal nuclear atypia.
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| Images:
| | DDx: |
| *[http://commons.wikimedia.org/wiki/File:Goblet_cell_carcinoid_-2-_very_high_mag.jpg GCC - very high mag. (WC)]. | | *[[Acute appendicitis]]. |
| *[http://commons.wikimedia.org/wiki/File:Goblet_cell_carcinoid_-_very_low_mag.jpg GCC - very low mag. (WC)].
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| ===Stains=== | | =Tumours of the appendix= |
| *Mucin stains +ve: | | ==Adenocarcinoma== |
| **Mucicarmine, perodic acid-Schiff diastase (PAS-D), alician blue.
| | *Like ''colorectal adenocarcinoma'' - see ''[[colorectal tumours]]''. |
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| ====IHC====
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| *Classic neuroendocrine markers:
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| **Synaptophysin +ve.
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| **Chromogranin +ve.
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| *S100 +ve.
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| *NSE +ve.
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| *Serotonin +ve.
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| Keratins:
| | ==Mucinous tumours of the appendix== |
| *Usually CK20 +ve > CK7 +ve.
| | {{Main|Mucinous tumours of the appendix}} |
| | This grouping includes ''mucinous cystadenoma'' and ''mucinous cystadenocarcinoma''. |
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| *CEA +ve (membrane). | | ==Goblet cell adenocarcinoma== |
| | {{Main|Goblet cell adenocarcinoma}} |
| | *Previously known as ''goblet cell carcinoid''. |
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| Notes:
| | ==Neuroendocrine tumour of the appendix== |
| *Nice review of stains in Pahlavan and Kanthan.<ref name=pmid15967038>{{cite journal |author=Pahlavan PS, Kanthan R |title=Goblet cell carcinoid of the appendix |journal=World J Surg Oncol |volume=3 |issue= |pages=36 |year=2005 |month=June |pmid=15967038 |pmc=1182398 |doi=10.1186/1477-7819-3-36 |url=http://wjso.com/content/3/1/36}}</ref> | | *Previously known as ''appendiceal carcinoid''. |
| | *[[AKA]] ''appendiceal neuroendocrine tumour'', abbreviated ''appendiceal NET''. |
| | {{Main|Neuroendocrine tumour of the appendix}} |
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| =See also= | | =See also= |
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| [[Category:Gastrointestinal pathology]] | | [[Category:Gastrointestinal pathology]] |
| | [[Category:Vermiform appendix]] |