Difference between revisions of "Neuroendocrine tumour of the appendix"

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#redirect [[Vermiform_appendix#Neuroendocrine_tumour_of_the_appendix]]
'''Neuroendocrine tumour of the appendix''' is a common tumour of the [[vermiform appendix]]. It is also known as '''appendiceal neuroendocrine tumour''', abbreviated '''appendiceal NET'''.
 
It was previously known as '''appendiceal [[carcinoid]]'''.
 
==General==
*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.
 
Management:
*Simple resection, e.g. appendectomy, sufficient for most tumours <2 cm.<ref name=pmid25840530>{{Cite journal  | last1 = Nussbaum | first1 = DP. | last2 = Speicher | first2 = PJ. | last3 = Gulack | first3 = BC. | last4 = Keenan | first4 = JE. | last5 = Ganapathi | first5 = AM. | last6 = Englum | first6 = BR. | last7 = Tyler | first7 = DS. | last8 = Blazer | first8 = DG. | title = Management of 1- to 2-cm Carcinoid Tumors of the Appendix: Using the National Cancer Data Base to Address Controversies in General Surgery. | journal = J Am Coll Surg | volume = 220 | issue = 5 | pages = 894-903 | month = May | year = 2015 | doi = 10.1016/j.jamcollsurg.2015.01.005 | PMID = 25840530 }}</ref><ref name=pmid18338494>{{Cite journal  | last1 = Fornaro | first1 = R. | last2 = Frascio | first2 = M. | last3 = Sticchi | first3 = C. | last4 = De Salvo | first4 = L. | last5 = Stabilini | first5 = C. | last6 = Mandolfino | first6 = F. | last7 = Ricci | first7 = B. | last8 = Gianetta | first8 = E. | title = Appendectomy or right hemicolectomy in the treatment of appendiceal carcinoid tumors? | journal = Tumori | volume = 93 | issue = 6 | pages = 587-90 | month =  | year =  | doi =  | PMID = 18338494 }}</ref>
 
==Gross==
*Classically found in the tip of the appendix.
*Characteristic yellow cut surface post-[[fixation]].
*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, [[rosette]]s.
*Fibrous stroma in between cell groups.
*Cytomorphology:
**Monotonous appearance with scanty mitoses.
**Round central nuclei.
**Stippled chromatin ([[AKA]] ''salt-and-pepper chromatin'' and ''coarse chromatin'').
**Eosinophilic granular cytoplasm.
 
DDx:
*[[Colorectal adenocarcinoma]].
*Adenocarcinoid.
*[[Crypt cell carcinoma]], also known as ''goblet cell carcinoid''.
*[[Metastasis|Metastatic]] [[adenocarcinoma]].
*Normal ganglion cells in the Meissner plexus (submucosa) and Auerbach plexus (located between the inner and outer layers of the muscularis propria).
 
===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 - dealt with in the article ''[[crypt cell carcinoma]]''.
*Signet-ring cells forming glandular structures.
*Possibly also with extra-cellular mucin.{{fact}}
 
===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.{{fact}}
*S100 positive for appendix.{{fact}}
 
Others:
*CK7 and CK20 variable.<ref name=pmid22461652>{{Cite journal  | last1 = Matsukuma | first1 = KE. | last2 = Montgomery | first2 = EA. | title = Tubular carcinoids of the appendix: the CK7/CK20 immunophenotype can be a diagnostic pitfall. | journal = J Clin Pathol | volume = 65 | issue = 7 | pages = 666-8 | month = Jul | year = 2012 | doi = 10.1136/jclinpath-2011-200639 | PMID = 22461652 }}</ref>
 
==Sign out==
<pre>
Vermiform Appendix, Appendectomy:
    - Low-grade neuroendocrine tumour (carcinoid tumour), see comment.
    -- Margins clear.
    -- Please see synoptic report.
    - Perforated acute appendicitis with periappendicitis.
 
Comment:
The tumour stains as follows:
POSITIVE: AE1/AE3, chromogranin A, synaptophysin, CD56.
NEGATIVE: CK7, CK20, S100.
PROLIFERATION (Ki-67): <3%.
 
The low-grade neuroendocrine tumour (in the planes of section) is in the tip and
separate from the appendiceal perforation site/acute appendicitis.
 
The specimen was submitted in total.
</pre>
 
==See also==
*[[Vermiform appendix]].
*[[Neuroendocrine tumours]].
 
==References==
{{Reflist|2}}


[[Category:Diagnosis]]
[[Category:Diagnosis]]
[[Category:Vermiform appendix]]

Latest revision as of 14:41, 22 August 2019

Neuroendocrine tumour of the appendix is a common tumour of the vermiform appendix. It is also known as appendiceal neuroendocrine tumour, abbreviated appendiceal NET.

It was previously known as appendiceal carcinoid.

General

  • Most common tumour of the appendix.[1]
    • Not really common though - one is seen in approximately 300 appendectomies.[2]

Presentation

    • Often found incidentally, may be microscopic.
    • May cause obstruction leading to mucocele or acute appendicitis.
    • May precipitate torsion.

Size matters in appendiceal NETs:[3]

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

Management:

  • Simple resection, e.g. appendectomy, sufficient for most tumours <2 cm.[4][5]

Gross

  • Classically found in the tip of the appendix.
  • Characteristic yellow cut surface post-fixation.
  • Circumscribed but not encapsulated.
  • Firm (due to desmoplasia).
  • Centred in the submucosa.
  • Nodules that do not usually cause erosion of the overlying mucosa.

Image

  • Appendiceal neuroendocrine tumour. (WC)

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 and coarse chromatin).
    • Eosinophilic granular cytoplasm.

DDx:

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 - dealt with in the article crypt cell carcinoma.
  • Signet-ring cells forming glandular structures.
  • Possibly also with extra-cellular mucin.[citation needed]

Images

  • Appendiceal carcinoid with torsion of the appendix - 1x (SKB)

  • Appendiceal carcinoid with torsion of the appendix - low power (SKB)

  • Appendiceal carcinoid with torsion of the appendix - medium power (SKB)

  • Appendiceal carcinoid - low power (SKB)

  • Appendiceal carcinoid - high power (SKB)

  • Appendiceal carcinoid - synaptophysin (SKB)

  • Appendiceal carcinoid - low power (SKB)

  • Appendiceal carcinoid - high power (SKB)

  • Appendiceal carcinoid - low power (SKB)

  • Appendiceal carcinoid with necrosis (SKB)

www:

IHC

Features:

Others:

  • CK7 and CK20 variable.[6]

Sign out

Vermiform Appendix, Appendectomy:
     - Low-grade neuroendocrine tumour (carcinoid tumour), see comment.
     -- Margins clear. 
     -- Please see synoptic report.
     - Perforated acute appendicitis with periappendicitis.

Comment:
The tumour stains as follows:
POSITIVE: AE1/AE3, chromogranin A, synaptophysin, CD56.
NEGATIVE: CK7, CK20, S100.
PROLIFERATION (Ki-67): <3%.

The low-grade neuroendocrine tumour (in the planes of section) is in the tip and 
separate from the appendiceal perforation site/acute appendicitis.

The specimen was submitted in total.

See also

References

  1. ↑ 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.
  2. ↑ 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.
  3. ↑ 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.
  4. ↑ Nussbaum, DP.; Speicher, PJ.; Gulack, BC.; Keenan, JE.; Ganapathi, AM.; Englum, BR.; Tyler, DS.; Blazer, DG. (May 2015). "Management of 1- to 2-cm Carcinoid Tumors of the Appendix: Using the National Cancer Data Base to Address Controversies in General Surgery.". J Am Coll Surg 220 (5): 894-903. doi:10.1016/j.jamcollsurg.2015.01.005. PMID 25840530.
  5. ↑ Fornaro, R.; Frascio, M.; Sticchi, C.; De Salvo, L.; Stabilini, C.; Mandolfino, F.; Ricci, B.; Gianetta, E.. "Appendectomy or right hemicolectomy in the treatment of appendiceal carcinoid tumors?". Tumori 93 (6): 587-90. PMID 18338494.
  6. ↑ Matsukuma, KE.; Montgomery, EA. (Jul 2012). "Tubular carcinoids of the appendix: the CK7/CK20 immunophenotype can be a diagnostic pitfall.". J Clin Pathol 65 (7): 666-8. doi:10.1136/jclinpath-2011-200639. PMID 22461652.
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