Appendix
Carcinoma
Adenocarcinoma


Topic Completed: 1 August 2012

Revised: 23 January 2019

Copyright: (c) 2003-2019, PathologyOutlines.com, Inc.

PubMed Search: Adenocarcinoma appendix
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Cite this page: Mansouri J. Adenocarcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/appendixadenocarcinoma.html. Accessed March 22nd, 2019.
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
Gross description
  • Cystic (cystadenocarcinoma, see below) or noncystic
  • Appendix may be buried within the mass
Microscopic (histologic) description
  • Intestinal, mucinous or signet ring cell types, invasive
  • Often coexisting acute appendicitis
Molecular / cytogenetics description
Positive stains
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
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