Difference between revisions of "Neuroendocrine tumour of the appendix"

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*Classically subepithelial/mural.  
*Classically subepithelial/mural.  
*Various growth patterns:
*Various growth patterns:
**Nested (insular)
**Nested (insular).
**Trabecular
**Trabecular.
**Palisading  
**Palisading.
**Ribbons, rosettes
**Ribbons, [[rosette]]s.
*Fibrous stroma in between cell groups.
*Fibrous stroma in between cell groups.
*Cytomorphology
*Cytomorphology:
**Monotonous appearance with scanty mitoses.
**Monotonous appearance with scanty mitoses.
**Round central nuclei
**Round central nuclei.
**Stippled chromatin [[AKA]] salt-and-pepper chromatin, coarse chromatin.
**Stippled chromatin ([[AKA]] ''salt-and-pepper chromatin'' and ''coarse chromatin'').
**Eosinophilic granular cytoplasm
**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===
===Special Types===
*Tubular carcinoid  
*Tubular carcinoid.
**Neuroendocrine cells forming tubules (no cell nests)
**Neuroendocrine cells forming tubules (no cell nests).
**Some tubules can contain mucin  
**Some tubules can contain mucin.
**Can be confused with adenocarcinoma  
**Can be confused with adenocarcinoma.
**Features suggesting tubular carcinoid (over adenocarcinoma):
**Features suggesting tubular carcinoid (over adenocarcinoma):
***Arises from base of crypts, with no disruption of surface epithelium.
***Arises from base of crypts, with no disruption of surface epithelium.
***No associated epithelial precursor (no adenomatous change).
***No associated epithelial precursor (no adenomatous change).
***Neuroendocrine cytologic features, without prominent atypia  
***Neuroendocrine cytologic features, without prominent atypia.
***IHC (NE markers +ve)  
***IHC (NE markers +ve).
 
*Goblet cell carcinoid - dealt with in the article ''[[crypt cell carcinoma]]''.
*Goblet cell carcinoid aka [[Crypt cell carcinoma]]
*Signet-ring cells forming glandular structures.
*Signet-ring cells forming glandular structures,
*Possibly also with extra-cellular mucin.{{fact}}
*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===
===Images===
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*Chromogranin A -ve/+ve.
*Chromogranin A -ve/+ve.
*Synaptophysin +ve.
*Synaptophysin +ve.
*Keratin positive, but CK7/CK20 negative  
*Keratin positive, but CK7/CK20 negative.{{fact}}
*S100 positive for appendix  
*S100 positive for appendix.{{fact}}
 
See: ''''.


==See also==
==See also==

Revision as of 07:35, 19 March 2015

Neuroendocrine tumour of the appendix is a common tumour of the vermiform appendix.

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.

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

  • 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:

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.
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