Home   Chapter Home   Jobs   Conferences   Fellowships   Books



Advertisement

Appendix

Other tumors

Gastrointestinal stromal tumors (GIST)


Reviewer: Jaleh Mansouri, M.D. (see Reviewers page)
Revised: 20 October 2012, last major update August 2012
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.

General
=========================================================================

● Very rare (only 4 cases at AFIP during 1970-1998, Am J Surg Pathol 2001;25:1433)
● Mean age 56-72 years
● Associated with appendicitis-like symptoms or incidental findings
● No deaths due to primary appendiceal GIST, but appendix may also be site of metastases
● Appear to follow indolent course although GIST with malignant features in appendix has been described (J Gastrointest Cancer 2010;41:9)

Gross description
=========================================================================

● Partially obliterating nodules expanding appendiceal wall

Micro description
=========================================================================

● Spindle cell tumor, often with extracellular collagen globules (skenoid fibers)
● No atypia, no mitotic activity

Molecular description
=========================================================================

● One series with 2 appendiceal GISTS identified KIT mutations at exon 11 (Hum Pathol 2008;39:1252)

Positive stains
=========================================================================

● CD117, CD34 (often)

Negative stains
=========================================================================

● Alpha smooth muscle actin, S100

Differential diagnosis
=========================================================================

● Inflammatory fibrous polyp
● Leiomyosarcoma: actin+, desmin+
Neurofibroma
● Schwannoma: often microtrabecular pattern with surrounding lymphoid cuff, S100+, CD117-, actin-

End of Appendix > Other tumors > Gastrointestinal stromal tumors (GIST)


This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information).