Oncology & Hematology Coding Alert

Question: How do I code a gastrointestinal stromal tumor (GIST)?

Georgia Subscriber

Answer: Accurate GIST coding relies on knowing the exact location of the tumor. Most start in the stomach and are also common in the small intestine, though they can occur anywhere in the GI tract.

If your provider has only indicated GIST in the patient’s notes, the default code to use is C49.A0 (Gastrointestinal stromal tumor, unspecified site). However, if your provider has specified the tumor site, you can use a more specific code from the following:

• C49.A1 (Gastrointestinal stromal tumor of esophagus)
• C49.A2 (Gastrointestinal stromal tumor of stomach)
• C49.A3 (Gastrointestinal stromal tumor of small intestine)
• C49.A4 (Gastrointestinal stromal tumor of large intestine)
• C49.A5 (Gastrointestinal stromal tumor of rectum)

A GIST in a location specified by your provider that is not in any of the above GI locations would be coded with C49. A9 (Gastrointestinal stromal tumor of other sites). And while most GISTs are malignant in nature, if your provider notes that it is benign, you can use D21.4 (Benign neoplasm of connective and other soft tissue of abdomen) as directed by the alphabetical index.