Appendix

Background

The appendix is commonly removed due to appendicitis but also may be resected in colectomies or other surgery. 1

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False positive and false negative diagnoses of appendicitis occur preoperatively. Clinical symptoms vary 2 and normal appendiceal diameters overlap cases of inflamed appendix on imaging. 3,4

Oedema, purulent serosal exudate or perforation may be present but appendicitis is not always evident macroscopically. 1 It is recommended that all tissue is examined carefully before stating that no inflammation is present. 5

While tumours of the appendix are uncommon, neuroendocrine (carcinoid) tumours and adenocarcinomas do occur  6,7 and can be incidental findings in cases of appendicitis (found in 0.1 to 0.6 per cent of appendectomies) 1. In these cases, more extensive sampling of the appendix is required 8. It is suggested that the appendicular and mesoappendicular resection margins as well as lymph nodes should be submitted for processing. A review of the serosal surface for any abnormalities would also be recommended. 9


Record the patient identifying information and any clinical information supplied together with the specimen description as designated on the container. See overview page for more detail on identification principles.

Fresh tissue received
  • No
    • Non-routine fixation (not formalin), describe.
  • Yes
    • Special studies required, describe.
    • Ensure samples are taken prior to fixation.
Intraoperative consultation
  • Not performed
  • Performed, describe type and result
    • Frozen section
    • Imprints
    • Other, describe

See general information for more detail on specimen handling procedures.

Inspect the specimen and dictate a macroscopic description.

External InspectionBack to top


Orientate and identify anatomical features of the specimen including appendix tip and proximal margin.

Describe the following features of the specimen:

Procedure

Record as stated by the clinician.
  • Appendicectomy
  • Right hemicolectomy and appendicectomy see colorectal tumour protocol

Anatomical components included (more than one may apply) and dimensions (mm)

Describe and measure the anatomical components present.

  • Appendix, in two dimensions
    • Length and diameter
  • Mesoappendix, two dimensions
  • Other, describe and measure according to the relevant tissue protocol.

Specimen integrity

  • Intact
  • Disrupted/piecemeal
    • Number of pieces

Shape of appendix

  • Normal (vermiform)
  • Distended
  • Mucocoele

Outer surface (more than one may apply)

  • Unremarkable
  • Haemorrhagic
  • Perforation
    • Location and size (mm)
  • Adhesions
  • Fibrotic
  • Purulent
  • Mucin
  • Tumour present
More detail

Macroscopic appearance of some disease processes seen in appendix: 1

Disease process
Macroscopic appearance
Neuroendocrine tumours (carcinoid)
May not be obvious macroscopically but can be large, firm, yellow-white, well circumscribed, unencapsulated tumours often in swollen tip of appendix
Endometriosis
Hypertrophied muscularis propria with focal haemorrhage
Mucocoele, mucinous cystadenoma and mucinous cystadenocarcinoma
Enlarged diffusely globular appendix with mucus in lumen
Adenocarcinoma
mucinous cystadenoma and mucinous cystadenocarcinoma –enlarged diffusely globular appendix with mucus in lumen
Appendicitis due to a caecal diverticulum
Normal appendix with pericaecal abscess leading from a caecal diverticulum

DissectionBack to top


Section the distal third (tip) of the appendix longitudinally and transversely section the remaining two-thirds to the resection margin.

Internal InspectionBack to top


Describe the internal appearance including the following items:

More detail

Describe the mucosal surface and the contents of the lumen. Note any thickening or narrowing of the mucosa or lumen; presence of faecoliths, foreign bodies, fibrous obliteration, mucin and parasites and presence or absence of any lesions such as tumours.

Mucosa

  • Unremarkable
  • Congested
  • Fibrinous

Lumen contents

  • Faecoliths
    • Number
    • Maximum size (mm)
  • Location
    • Embedded in wall
    • Distending wall
  • Mucin
  • Foreign bodies
  • Parasites
  • Fibrous obliteration

Tumour

  • Absent
  • Present
    • Number; if more than one tumour, designate and describe each tumour separately:
Tumour specimen description

Tumour size(mm)

  • Maximum dimension

Tumour location(s)

(more than one may apply)
  • Tip of appendix
  • Middle third
  • Proximal third

Tumour penetration

  • Confined to mucosa
  • Into muscularis propria
  • Into mesoappendix
  • Into other organ, specify

Serosal involvement

  • Absent
  • Suspicious
  • Involved

Distance from surgical margins (mm)

  • Proximal margin
  • Closer (ileal or colonic) margin if right hemicolectomy

Note any photographs taken, diagrams recorded, ink or marks used for identification.

ProcessingBack to top


Submit representative sections for processing according to the images provided.

Non-tumour specimens

Macroscopically inflamed appendix

Submit representative sections:

  • Longitudinal section of apex (distal tip)
  • Transverse sections of body
  • Transverse section from resection (proximal) margin 2
Macroscopically normal appendix

Submit all tissue for processing. (It may be necessary to process the entire specimen before reporting that there is no inflammation). 8

Tumour specimens

Solid tumour

Submission of all tumour tissue  for processing may be appropriate.

Designate the section representing the point of deepest invasion and process in separate cassette.

Select and denote sections representing:

  • Deepest point of invasion
  • Possible serosal involvement
  • Edge of tumour to proximal margin if <10mm
Mucocoele (possible appendiceal mucinous neoplasm)

In most cases no obvious solid tumour is evident. Thorough sampling of the mucocoele wall is recommended focusing on any cystic/mucous deposits within the wall or on the serosal surface.

Designate the section representing the point of deepest invasion and process in a separate cassette.

Select and denote sections representing:

  • Deepest point of invasion
  • Possible serosal involvement
  • Edge of tumour to proximal margin if <10mm
  • Adjacent background appendiceal mucosa

Record details of each cassette.

An illustrated block key similar to the one provided may be useful.

Block allocation key

Macroscopically inflamed appendix
Cassette id
Site
No. of pieces
A
Distal tip and proximal margin
 
B
Representative sections of body
 
Macroscopically normal appendix
Cassette id
Site
No. of pieces
A
Distal tip and proximal margin
 
B
All sections of body
 
Appendix with solid tumour
Cassette id
Site
No. of pieces
A
Proximal margin
 
B
Tumour with deepest point of invasion
 
C
Tumour with serosal involvement (if applicable)
 
D
Tumour, representative sections
 
E
Distal tip
 
Appendix with mucocoele
Cassette id
Site
No. of pieces
A
Proximal margin
 
B
Tumour with deepest point of invasion (if applicable)
 
C
Tumour with serosal involvement (if applicable)
 
D-E
Tumour/mucocoele wall, representative sections
 
F
Tumour with proximal margin (if applicable)
 
G
Appendiceal mucosa, representative sections
 

Acknowledgements

Dr Ian Brown for his contribution in reviewing and editing this protocol.

ReferencesBack to top


  1. Lester SC. Appendix. In: Manual of Surgical Pathology, Saunders Elsevier, Philadelphia, 2010;355-359.
  2. Graff L, Russell J, Seashore J, Tate J, Elwell A, Prete M, Werdmann M, Maag R, Krivenko C and Radford M. False-negative and false-positive errors in abdominal pain evaluation: failure to diagnose acute appendicitis and unnecessary surgery. Acad Emerg Med 2000;7(11):1244-1255.
  3. Webb EM, Wang ZJ, Coakley FV, Poder L, Westphalen AC and Yeh BM. The equivocal appendix at CT: prevalence in a control population. Emerg Radiol 2010;17(1):57-61.
  4. Karabulut N, Boyaci N, Yagci B, Herek D and Kiroglu Y. Computed tomography evaluation of the normal appendix: comparison of low-dose and standard-dose unenhanced helical computed tomography. J Comput Assist Tomogr 2007;31(5):732-740.
  5. Odze RD. Surgical pathology of the GI tract, liver, biliary tract and pancreas. Goldblum J. Saunders Elsevier, Philadelphia, 2009.
  6. McGory ML, Maggard MA, Kang H, O'Connell JB and Ko CY. Malignancies of the appendix: beyond case series reports. Dis Colon Rectum 2005;48(12):2264-2271.
  7. Sandor A and Modlin IM. A retrospective analysis of 1570 appendiceal carcinoids. Am J Gastroenterol 1998;93(3):422-428.
  8. Stephenson TJ, Cross SS and Chetty R. Dataset for neuroendocrine tumours of the gastrointestinal tract including pancreas, 3rd ed. The Royal College of Pathologists, London, 2012.
  9. Williams GT, Quirke P and Shepherd NA. Dataset for colorectal cancer, 2nd ed. The Royal College of Pathologists, London, 2007.