2026 ICD-10-CM Diagnosis Code C49.4Malignant neoplasm of connective and soft tissue of abdomen

ICD-10-CM Codes›C00–D49›C45-C49›C49

ICD-10-CM C49.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C49.4 is a billable ICD-10-CM diagnosis code for malignant neoplasm of connective and soft tissue of abdomen. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 542 through 544. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sarcoma.

Code Identity

ICD-10-CM Code
C49.4
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of connective and soft tissue of abdomen
Short Description
Malignant neoplasm of connective and soft tissue of abdomen
Same as the full description in the CMS dataset.
Parent Code
C49
Malignant neoplasm of other connective and soft tissue

Code Classification

ChapterC00–D49Neoplasms
SectionC45-C49Malignant neoplasms of mesothelial and soft tissue
CategoryC49Malignant neoplasm of other connective and soft tissue
This CodeC49.4Malignant neoplasm of connective and soft tissue of abdomen

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Fibrosarcoma
  • Fibrosarcoma of spleen
  • Malignant neoplasm of soft tissue of abdomen
  • Neoplasm of blood vessel of abdomen
  • Neoplasm of muscle of abdomen
  • Primary angiosarcoma of abdomen
  • Primary angiosarcoma of trunk
  • Primary leiomyosarcoma of abdomen
  • Primary liposarcoma of soft tissue of abdomen
  • Primary liposarcoma of soft tissue of trunk
  • Primary malignant fibrous histiocytoma of abdomen
  • Primary malignant neoplasm of blood vessel of abdomen
  • Primary malignant neoplasm of blood vessel of trunk
  • Primary malignant neoplasm of muscle of abdomen
  • Primary malignant neoplasm of muscle of trunk
  • Primary malignant neoplasm of soft tissues of abdomen
  • Primary rhabdomyosarcoma of abdomen
  • Primary sarcoma of soft tissues of abdomen

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Malignant neoplasm of abdominal wall
  • Malignant neoplasm of hypochondrium

Clinical ClassificationClinical

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

CCSR NEO024
Sarcoma
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Dermatofibrosarcoma

    a sarcoma of the deep layers of the skin. the tumors are locally aggressive tends to recur but rarely metastatic. it can be classified into variants depending on the cell type tumors are derived from or by its characteristics: pigmented variant from melanin-containing dermal dendritic cells; myxoid variant, myxoid stromal cells; giant cell variant characterized by giant cells in the tumors; and fibrosarcomatous variant chracterized by tumor areas histologically indistinguishable from fibrosarcoma.

  • Fibrosarcoma

    a sarcoma derived from deep fibrous tissue, characterized by bundles of immature proliferating fibroblasts with variable collagen formation, which tends to invade locally and metastasize by the bloodstream. (stedman, 25th ed)

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
abdomen, abdominal › wall [See Also: Neoplasm, abdomen, wall, skin] › connective tissueC49.4C79.8–D21.4D48.1D49.2
adipose tissue [See Also: Neoplasm, connective tissue]C49.4C79.89–D21.9D48.1D49.2
aorta (thoracic) › abdominalC49.4C79.89–D21.4D48.1D49.2
connective tissue NEC › abdomenC49.4C79.89–D21.4D48.1D49.2
connective tissue NEC › abdominal wallC49.4C79.89–D21.4D48.1D49.2
connective tissue NEC › gastricC49.4C79.89–D21.4D48.1D49.2
connective tissue NEC › gastrointestinalC49.4C79.89–D21.4D48.1D49.2
connective tissue NEC › hypochondriumC49.4C79.89–D21.4D48.1D49.2
connective tissue NEC › intestinalC49.4C79.89–D21.4D48.1D49.2
connective tissue NEC › psoas muscleC49.4C79.89–D21.4D48.1D49.2
connective tissue NEC › stomachC49.4C79.89–D21.4D48.1D49.2
connective tissue NEC › umbilicusC49.4C79.89–D21.4D48.1D49.2
vena cava (abdominal) (inferior)C49.4C79.89–D21.4D48.1D49.2

Patient EducationClinical

Cancer

Cancer is not just one disease but many diseases. Cancer begins in your cells, which are the building blocks of your body. Usually, your body forms new cells as needed, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don't need them, and old cells don't die when they should.

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Read the full article at MedlinePlus

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

Convert C49.4 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 HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About C49.4Overview

Is C49.4 (Malignant neoplasm of other connective and soft tissue) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of connective and soft tissue of abdomen on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C49.4 group to?

When malignant neoplasm of connective and soft tissue of abdomen is the principal diagnosis on an inpatient stay, it groups to MS-DRG 542, 543, 544, with relative weights from 0.7546 to 1.7665 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C49.4?

Under the General Equivalence Mappings, malignant neoplasm of connective and soft tissue of abdomen 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.