Appendix
Carcinoma
Adenocarcinoma

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

Revised: 29 February 2016, last major update August 2012

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

PubMed Search: Adenocarcinoma appendix
Cite this page: Adenocarcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/appendixadenocarcinoma.html. Accessed December 4th, 2016.
Clinical Features
  • Rare, 0.2% of appendectomy specimens
  • Usually ages 40-69 years (similar to colonic adenocarcinoma)
  • 75% are symptomatic, with symptoms of acute appendicitis, abdominal mass or intestinal obstruction
  • Also associated with appendiceal adenoma or rupture of appendix
  • Mucinous cases typically present with pseudomyxoma peritonei
  • Cases with mixed carcinoid-adenocarcinoma behave as adenocarcinoma
  • Ulcerative colitis and familial adenomatous polyposis appear to confer increased susceptibility
  • Patients with incidental appendiceal epithelial tumors are at risk for synchronous colonic lesions and should undergo colonoscopy
  • Treatment
  • Appendectomy if well-differentiated and superficial, otherwise right hemicolectomy
  • Case Reports
  • 35 year old woman with mixed small cell carcinoma and intestinal type adenocarcinoma (Am J Surg Pathol 2004;28:1233)
  • Gross Description
  • Cystic (cystadenocarcinoma, see below) or noncystic
  • Appendix may be buried within the mass
  • Micro Description
  • Intestinal, mucinous or signet ring cell types, invasive
  • Often coexisting acute appendicitis
  • Micro Images

    Images hosted on other servers:

    Low grade mucinous adenocarcinoma

    Moderately differentiated nonmucinous adenocarcinoma

    Signet ring cell carcinoma

    Intestinal (colonic) type

    Molecular / Cytogenetics Description
  • Kras mutations in 55% (Mod Pathol 2002;15:599), 18q-, usually no microsatellite instability present
  • Positive Stains
  • MUC2 (Mod Pathol 2003;16:403), MUC5AC (67%), CK8/18, CK13, CK19, CK20
  • Negative Stains
  • MUC1 (usually), MUC6, CK7 (usually), CK14, p53
  • Differential Diagnosis
  • Metastatic gastric or breast carcinoma (for signet ring types)
  • Large cecal carcinomas may involve base of appendix