Oncology & Hematology Coding Alert

Question: What is the appropriate code for GIST, and how do I find it?

California Subscriber

Answer: GIST is defined as a gastrointestinal stromal tumor. To find the proper diagnosis code for GIST, start in the ICD-10-CM index by looking up “tumor.” Under “tumor,” locate the term “stromal” and then find “gastrointestinal.”

The index then points you to different codes based on the information available in the documentation. 

If GIST is the only information you have, the index points to C49.A- (Gastrointestinal stromal tumor). Keep in mind: You will still need a fifth character but without any additional information, report C49.A0 (…unspecified site).

Underneath the gastrointestinal determination in your Alphabetic Index, you’ve got additional options if the information is available in the documentation.

Benign: For instance, if the documentation indicates a benign GIST, you’ll use D21.4 (Benign neoplasm of connective and other soft tissue of abdomen). GIST includes tumors of the gastrointestinal system.  However, it is important to note ‘stromal tumors’ could occur at other anatomical sites. If the site is not gastrointestinal, look for the correct site to classify the tumor.  For stromal tumors at other locations, search in the neoplasm table for main term connective tissue NEC. Then find the appropriate sub term (location) for your code in the column labeled Benign. Always follow up by looking up the code in the tabular list.