2026 ICD-10-CM Diagnosis Code C49.A0Gastrointestinal stromal tumor, unspecified site

ICD-10-CM Codes›C00–D49›C45-C49›C49

ICD-10-CM C49.A0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C49.A0 is a billable ICD-10-CM diagnosis code for gastrointestinal stromal tumor, unspecified site. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 374 through 376. Coders also document this condition as gastrointestinal stromal tumor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Gastrointestinal cancers - all other types.

Code Identity

ICD-10-CM Code
C49.A0
Billable Status
Yes — Valid for Submission
Code Describes
Gastrointestinal stromal tumor, unspecified site
Short Description
Gastrointestinal stromal tumor, unspecified site
Same as the full description in the CMS dataset.
Parent Code
C49.A
Gastrointestinal stromal tumor

Code Classification

ChapterC00–D49Neoplasms
SectionC45-C49Malignant neoplasms of mesothelial and soft tissue
CategoryC49Malignant neoplasm of other connective and soft tissue
This CodeC49.A0Gastrointestinal stromal tumor, unspecified site

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Gastrointestinal stromal tumor

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Tumor
      • stromal
        • gastrointestinal
          • malignant

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NEO021
Gastrointestinal cancers - all other types
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Gastrointestinal stromal tumor

A gastrointestinal stromal tumor (GIST) is a type of tumor that occurs in the gastrointestinal tract, most commonly in the stomach or small intestine. This type of tumor is thought to grow from specialized cells found in the gastrointestinal tract called interstitial cells of Cajal (ICCs) or precursors to these cells.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert C49.A0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
171.5 Mal neo soft tis abdomen
Approximate The match is approximate rather than exact.

Code History & ChangesHistory

Replacement C49.A0 replaces the following previously assigned code(s):

  • C49.4 - Malignant neoplasm of connective and soft tissue of abdomen
FY 2018AddedAdded to the ICD-10-CM code setEffective October 1, 2017.
FY 2019–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About C49.A0Overview

Is C49.A0 (Gastrointestinal stromal tumor) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report gastrointestinal stromal tumor, unspecified site on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C49.A0 group to?

When gastrointestinal stromal tumor, unspecified site is the principal diagnosis on an inpatient stay, it groups to MS-DRG 374, 375, 376, with relative weights from 0.9243 to 2.1387 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C49.A0?

Under the General Equivalence Mappings, gastrointestinal stromal tumor, unspecified site converts to ICD-9-CM 171.5 (mal neo soft tis abdomen). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.