C49.A2

Billable

Gastrointestinal stromal tumor of stomach

HCC Category Mapping

V28HCC 23 — Melanoma and Other Skin Cancers

0.251

V24HCC 10 — Lymphoma and Other Cancers

0.675

ESRDHCC 10 — Lymphoma and Other Cancers

0.000

RxHCCHCC 20 — Cancer, Liver and Intrahepatic Bile Duct

0.000

What This Code Means

A gastrointestinal stromal tumor (GIST) is a rare type of cancer that develops in the stomach from specialized nerve cells. These tumors can vary in size and aggressiveness, and may require surgery or targeted medication to treat.

Coding Tips

•Verify the tumor location is specifically the stomach; GISTs can occur in other parts of the digestive tract and require different codes (C49.A1 for esophagus, C49.A3 for small intestine, etc.)
•Ensure documentation includes whether the tumor is benign, uncertain behavior, or malignant, as this affects code selection and staging requirements

Clinical Significance

Gastrointestinal stromal tumor of the stomach is the most common GIST location, accounting for approximately 60-70% of all GISTs. Gastric GISTs generally have a better prognosis than small intestinal GISTs of the same size and mitotic rate, making accurate site-specific coding important for prognostic stratification.

Documentation Requirements

✓Pathology confirming GIST of gastric origin with immunohistochemistry (KIT/CD117, DOG1)
✓Specific gastric location (fundus, body, antrum, cardia)
✓Tumor size (critical for risk: <2cm, 2-5cm, 5-10cm, >10cm)
✓Mitotic rate per 50 high-power fields
✓Treatment plan (surgical resection, imatinib therapy, observation for small tumors)

Commonly Confused Codes

C16._ (Malignant neoplasm of stomach) — gastric adenocarcinoma, not GIST C49.A0 (GIST, unspecified site) — use C49.A2 when stomach is documented C49.A3 (GIST of small intestine) — different site with different prognosis D21.4 (Benign neoplasm of connective tissue of abdomen) — benign tumor, not malignant GIST

Code Hierarchy

└C49Malignant neoplasm of other connective and soft tissue └C49.AGastrointestinal stromal tumor └C49.A2Gastrointestinal stromal tumor of stomach

└C49.A2Gastrointestinal stromal tumor of stomach