ICD-10 Code C49.A3 – Gastrointestinal stromal tumor of small intestine (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C49.A3 – Gastrointestinal stromal tumor of small intestine
What it is
This code identifies a gastrointestinal stromal tumor arising in the small intestine. It is used when documentation specifies the tumor site as the small bowel rather than another GI location.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include a small intestinal mass, abdominal pain, bleeding, or incidental discovery on imaging or endoscopy.
When to use this code
Use C49.A3 when the provider documents a gastrointestinal stromal tumor of the small intestine, including duodenum, jejunum, or ileum if specified as small intestine. Code it from the final diagnosis, operative note, pathology report, or oncology assessment. Check documentation if the site is unclear or mixed with another GI location.
Do not use for
Do not use this code for GISTs documented in the stomach, colon, rectum, or other nonsmall-intestinal sites. Do not assign it when the record only says “GI tumor” or “sarcoma” without confirming GIST and small intestine.
Coding tip
Match the code to the exact anatomic site in the pathology or provider note; if the site is not explicit, check documentation before coding.