Understanding Your Pathology Report for Gastrointestinal Stromal Tumor (GIST)


Jason L. Hornick, MD PhD
Associate Professor
Harvard Medical School
Associate Director of Surgical Pathology
Director, Immunohistochemistry Laboratory
Department of Pathology
Brigham and Women’s Hospital
Boston, MA

Dr. Hornick has published approximately 100 original papers, review articles, and book chapters in soft tissue tumor pathology, gastrointestinal pathology, and diagnostic immunohistochemistry.  His research focuses on defining diagnostic criteria for soft tissue tumors and identifying features associated with malignancy and aggressive behavior.  He is also interested in translating scientific discoveries to clinical practice, to provide new tools for surgical pathology with the goals of improving tumor classification and identifying potential therapeutic targets.  When not working, he enjoys spending time with his wife and 7-year-old twins, a boy and a girl.


Alexander J.F. Lazar, MD PhD
Associate Professor
Department of Pathology
Sarcoma Research Center
Director, Sarcoma Molecular Diagnostics
The University of Texas M. D. Anderson Cancer Center
Houston, Texas

Alex Lazar is a sub-specialized pathologist concentrating solely on clinical diagnosis and molecular genotyping for sarcoma (and also genotyping for melanoma).  He is faculty in the multidisciplinary Sarcoma Research Center at M. D. Anderson Cancer Center with Drs. Dina Lev and Raphael Pollock with focus on early genetic changes in sarcomagenesis.  He has authored or co-authored  more than 100 publications on various aspects of sarcoma pathology and translational research (and a bit of related skin pathology).  He is a member of the American Joint Cancer Committee (AJCC) Soft Tissue Sarcoma (Staging) Task Force and Committee on Cancer subcommittees for Soft Tissue Sarcoma and GIST pathology reporting for the College of American Pathologists (CAP).  When not working, he enjoys spending time with his wife and children (aged 3 and 6 and very active), playing basketball and soccer/futsal, and foreign travel.  He is an assistant coach of his son’s soccer team and a big fan of international soccer.

assisted by

Julia D. Royster, PhD
Science Coordinator, GIST Support International

Julie is retired as an audiologist and psychologist who consulted and did research about industrial hearing conservation program effectiveness. She published journal articles, book chapters, and a practical text about hearing loss prevention, taught as an adjunct faculty member at UNC-Chapel Hill, and was a board member for professional associations.  Julie has studied GIST since 2003, when her husband Larry was diagnosed with gastrointestinal stromal tumor. Julie now volunteers as GSI science coordinator to make detailed information about GIST easily available to patients (one of the main missions of GSI).  Her interests include gardening, sewing, reading, and amateur astronomy.


Copyright 2010, GIST Support International

For a pdf of the print booklet version of this information click here.

Why is my pathology report important to me?

Your pathology report provides the diagnosis of the tumor that you had biopsied or surgically removed: gastrointestinal stromal tumor (GIST).   The specific tumor characteristics described in your pathology report help to determine which treatments are most appropriate for you.

Although the surgeon may suspect GIST on the basis of imaging done before your operation and the appearance of the tumor during surgery, only the pathologist can determine that the tumor is truly a GIST.  The pathologist makes the diagnosis by examining and testing the tissue from your tumor in the laboratory.  The pathologist describes tumor characteristics that can predict how likely it is to come back (recur) or to spread (metastasize) to your liver, your abdominal cavity, or other body parts.

Your oncologist will use the pathology report to help plan your treatment.  You should discuss your report with your oncologist to understand your GIST and your treatment choices.


What is a pathologist?

A pathologist is a medical doctor who diagnoses diseases by examining tissues, cells and bodily fluids.  In the case of GIST, the pathologist examines tissue from biopsies and surgeries.  After finishing medical school, a physician must complete a residency in pathology and pass an exam to become board certified as a pathologist.


What role does the pathologist play in my diagnosis and treatment planning?

Although patients rarely meet pathologists, they are crucial to your treatment because they:

  • Analyze pre-surgery biopsies to render a diagnosis
  • Diagnose GIST versus alternative tumor types to determine the therapeutic approach
  • Assess the adequacy of surgical margins after an operation
  • Determine the risk category (probability of recurrence) for primary tumors
  • Confirm any metastases already present at diagnosis
  • Provide the data to help decide whether imatinib will be used after a complete surgical resection of the primary tumor

Sections of this tutorial

Link to each of these subpages to read all about your GIST pathology report.

Diagnosing GIST

Pathology Methods for GIST

Pathology Analyses for GIST

GIST Prognosis: Risk of Recurrence or Aggressive Behavior

Pathology Reports for GIST

GIST Pathology Questions and Terminology

More GIST Pathology Resources