Other tumors

Reviewer: Jaleh Mansouri, M.D. (see Authors page)

Revised: 29 February 2016, last major update August 2012

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Carcinoid appendix
Cite this page: Carcinoid. website. Accessed October 25th, 2016.
Clinical Features
  • See also L cell carcinoid and goblet cell carcinoid

  • Appendix is common site for endocrine tumors, as well as tumors with multiple directional differentiation
  • Most common tumor of appendix, usually incidental (0.02% to 1.5% of all appendectomy specimens) and sporadic
  • Incidence peaks at ages 20-39 years, 20 years earlier than intestinal carcinoid
  • 20% of all GI carcinoids arise in appendix
  • Nodal metastases and metastatic spread are rare, even with transmural extension
  • 5 year survival is 85% even with regional metastases
  • Rare liver metastases may be associated with carcinoid syndrome
  • Treatment
  • Appendectomy usually is curative if less than 1 cm
  • Right hemicolectomy if > 2 cm or positive surgical margin or extremely pronounced mesoappendiceal spread
  • Perineural or angiolymphatic invasion are not predictive
  • Prognostic Factors
    For metastatic disease:
    Case Reports
  • 28 year old woman with hereditary nonpolyposis colorectal cancer syndrome, colonic adenocarcinoma with microsatellite instability and incidental appendiceal carcinoid tumor without microsatellite instability (Hum Pathol 2004;35:1564)
  • Gross Description
  • 70% at tip, usually < 1 cm
  • Gray or yellow, well-demarcated, firm, intramural nodules that may narrow or obliterate lumen
  • Proximal tumors may cause obstruction
  • Gross Images

    Images hosted on other servers:

    Gray-yellow tumor at tip of appendix

    Micro Description
  • Three histologic subtypes including classic, tubular, and goblet cell types, although combined classical carcinoid and goblet cell carcinoid tumor was recently described (Am J Surg Pathol 2010;34:1163)
  • May be diffusely within wall or along lumen
  • Tumors arise in mucosa but bulk is usually within muscularis propria with associated fibrosis and smooth muscle hypertrophy
  • Usually classic carcinoid insular growth pattern of solid islands of uniform polygonal cells with minimal pleomorphism, retraction of peripheral tumor cells from stroma
  • Tumor cells often within intraappendiceal nerves; angiolymphatic invasion is common
  • Cells have granular eosinophilic cytoplasm with either diffusely scattered or peripherally clumped granules
  • Rarely acinar pattern, clear cell/balloon cell pattern or vacuolated cells
  • No/rare mitotic activity
  • May penetrate mesoappendix
  • Two types of well differentiated tumors: EC cell (serotonin producing) and rarely L-cell (enteroglucagon or peptide YY producing, Hum Pathol 1990;21:773)
  • Tumor cells associated with S100+ Schwann-like cells (sustentacular cells)
  • Micro Images

    Images hosted on other servers:

    Islands of bland tumor cells; EM shows neurosecretory granules

    Molecular / Cytogenetics Description
  • May have 18q-, less frequently 11q-
  • Usually diploid by flow cytometry
  • Positive Stains
  • Chromogranin, neuron specific enolase, serotonin, substance P
  • Negative Stains
  • CEA, TTF1, CK7 (usually, Hum Pathol 2001;32:1087)