ICD-10 Code C49.A0 – Gastrointestinal stromal tumor, unspecified site (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C49.A0 – Gastrointestinal stromal tumor, unspecified site
What it is
This code identifies a gastrointestinal stromal tumor (GIST) when the record confirms the diagnosis but does not specify the anatomic site. Use it for a malignant stromal tumor arising in the gastrointestinal tract when location is not documented.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include an abdominal mass, gastrointestinal bleeding, pain, anemia, or incidental imaging discovery, but the diagnosis should be supported by pathology or specialist assessment.
When to use this code
Use C49.A0 when the provider documents GIST and the chart does not identify whether it is gastric, small bowel, or another site. It is also appropriate when a pathology report confirms GIST but the location remains unspecified in the available record. If the site is later clarified, code the more specific site instead.
Do not use for
Do not use this code for other gastrointestinal cancers, benign tumors, or nonspecific abdominal masses without a confirmed GIST diagnosis. Check documentation if the tumor site is known or if the record uses a different stromal neoplasm term.
Coding tip
Query for the primary site whenever the diagnosis is GIST but the location is missing, because a more specific code may be available.