ICD-10 Code C49.A5 – Gastrointestinal stromal tumor of rectum (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C49.A5 – Gastrointestinal stromal tumor of rectum
What it is
C49.A5 identifies a gastrointestinal stromal tumor located in the rectum. Use it for a documented rectal GIST, a mesenchymal tumor arising in the gastrointestinal tract.
Clinical signs
Clinical features vary; refer to documentation. Rectal GISTs may present as a rectal mass, bleeding, pain, or obstructive symptoms, and diagnosis is usually confirmed by pathology.
When to use this code
Use C49.A5 when the provider documents a gastrointestinal stromal tumor specifically in the rectum. Apply it for confirmed primary rectal GIST, including pathology-supported cases in clinic, surgical, or oncology records.
If the record only says “GIST” without site, check documentation before coding. Code the rectal site only when the anatomic location is clearly stated.
Do not use for
Do not use this code for stromal tumors in other GI sites or for nonspecific rectal masses without a confirmed GIST diagnosis. Check documentation if the site or pathology is unclear.
Coding tip
Verify both the tumor type and rectal location in the final pathology or provider assessment before assigning C49.A5.