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ICD-10-CM C49.A4: Gastrointestinal stromal tumor of large intestine

C49.A4 is the billable ICD-10-CM code for gastrointestinal stromal tumor of large intestine, in category C49 (Malignant neoplasm of other connective and soft tissue) of the Malignant neoplasms of mesothelial and soft tissue section. As a principal diagnosis it groups to MS-DRG 374 Digestive Malignancy with MCC, MS-DRG 375 Digestive Malignancy with CC, MS-DRG 376 Digestive Malignancy without CC/MCC (MDC 06 MDC 06: Diseases and Disorders of the Digestive System). It maps to HCC 23 (Prostate, Breast, and Other Cancers and Tumors) in CMS-HCC V28. As a secondary diagnosis it is a CC, excluded with 2 principal diagnoses. 48 LCD billing and coding articles list it as covered.

Compiled from CMS files by the QuickIntell RCM Editorial Team · Data effective · Method: reference methodology · Report a data correction

Data currency: ICD-10-CM code descriptions: FY2027 (effective October 1, 2026); IPPS Table 5 (MS-DRG weights): v44 FY2027 (final rule + CN3) (effective October 1, 2026); ICD-10-CM to HCC mapping: PY2027 initial ICD-10-CM mappings (dates of service 2026) (payment year 2027); Medicare Coverage Database billing and coding articles: MCD release October 8, 2026 (effective October 4, 2026). Next CMS release: FY2028 code files, effective October 1, 2027 for the ICD-10-CM code descriptions; FY2028 final rule (August 2027), effective October 1, 2027; an April 1 interim grouper update when CMS issues one for the IPPS Table 5 (MS-DRG weights); PY2028 advance notice (February 2027) and the PY2027 midyear final mapping (spring 2027) for the ICD-10-CM to HCC mapping; weekly, every Thursday for the Medicare Coverage Database billing and coding articles.

Code
C49.A4
billable FY2027 ICD-10-CM code
Category
C49 Malignant neoplasm of other connective and soft tissue
Chapter
2: Neoplasms (C00-D49)
CC/MCC (MS-DRG v44)
CC
CMS-HCC V28
HCC 23
POA reporting
Required

Tabular list notes for C49.A4

The tabular list has no notes on C49.A4 itself; the notes below apply from its parent headings.

Inherited from C49 (Malignant neoplasm of other connective and soft tissue)

Includes
  • malignant neoplasm of blood vessel
  • malignant neoplasm of bursa
  • malignant neoplasm of cartilage
  • malignant neoplasm of fascia
  • malignant neoplasm of fat
  • malignant neoplasm of ligament, except uterine
  • malignant neoplasm of lymphatic vessel
  • malignant neoplasm of muscle
  • malignant neoplasm of synovia
  • malignant neoplasm of tendon (sheath)
Excludes1 (never coded together)
  • malignant neoplasm of cartilage (of):
  • articular (C40-C41)
  • larynx (C32.3)
  • nose (C30.0)
  • malignant neoplasm of connective tissue of breast (C50.-)
Excludes2 (not part of this condition, may be coded together)
  • Kaposi's sarcoma of soft tissue (C46.1)
  • malignant neoplasm of heart (C38.0)
  • malignant neoplasm of peripheral nerves and autonomic nervous system (C47.-)
  • malignant neoplasm of peritoneum (C48.2)
  • malignant neoplasm of retroperitoneum (C48.0)
  • malignant neoplasm of uterine ligament (C57.3)
  • mesothelioma (C45.-)

MS-DRG grouping when C49.A4 is the principal diagnosis

MS-DRG v44 groups for C49.A4 as principal diagnosis
MDCMS-DRGs
06 MDC 06: Diseases and Disorders of the Digestive System374375376

The final group also depends on procedures, secondary diagnoses and discharge status; the MS-DRG lookup for C49.A4 shows the full grouping logic.

CC/MCC status and inpatient edits

As a secondary diagnosis, C49.A4 is a CC under MS-DRG v44, unless the principal diagnosis is one of the 2 codes in its exclusion list. Check C49.A4 against a principal diagnosis.

  • Present on admission: a POA indicator is required on inpatient claims.

CMS-HCC V28 risk adjustment

In the PY2027 mapping, C49.A4 maps to HCC 23 (Prostate, Breast, and Other Cancers and Tumors). The HCC lookup shows the RAF weight and the hierarchy.

LCD billing and coding articles that list C49.A4

48 current Medicare billing and coding articles list C49.A4 among the diagnoses that support medical necessity for the services they cover.

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Frequently asked questions

What does ICD-10-CM C49.A4 mean?

C49.A4 means gastrointestinal stromal tumor of large intestine. It is one of 20 billable codes under C49, malignant neoplasm of other connective and soft tissue.

Which MS-DRG does C49.A4 group to?

As the principal diagnosis, C49.A4 groups to MS-DRG 374 Digestive Malignancy with MCC, MS-DRG 375 Digestive Malignancy with CC, MS-DRG 376 Digestive Malignancy without CC/MCC (MDC 06 MDC 06: Diseases and Disorders of the Digestive System) under MS-DRG v44, before procedures and secondary diagnoses are applied.

Does C49.A4 map to an HCC?

Yes: HCC 23, Prostate, Breast, and Other Cancers and Tumors, in the PY2027 CMS-HCC V28 mapping.

Is C49.A4 a CC or MCC?

C49.A4 is a CC under MS-DRG v44; 2 principal diagnoses exclude it.

Sources

Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-10. Verify against the primary file before billing or contracting decisions. The reference methodology explains how each figure is computed from these files.

Disclaimer

The descriptor and notes are reproduced from the FY2027 ICD-10-CM files; MS-DRG, CC/MCC and HCC facts come from the CMS FY2027 and PY2027 tables. Code from the medical record and the ICD-10-CM Official Guidelines. Not legal, clinical or billing advice.

Found a figure that does not match the CMS file? Report a data correction with the CMS file and the value you expected; the request reaches the editorial team through the contact form.