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
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 23
- Chronic Condition
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. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 2 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sarcoma.
For Medicare Advantage risk adjustment, C49.4 maps to CMS-HCC Category 23 (Prostate, Breast, and Other Cancers and Tumors) under the V28 model, adding a risk factor of about 0.186 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C49.4 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.
Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
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
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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.
| Site | Malig. Primary | Malig. Secondary | Ca in situ | Benign | Uncertain | Unspec. |
|---|---|---|---|---|---|---|
| abdomen, abdominal › wall [See Also: Neoplasm, abdomen, wall, skin] › connective tissue | C49.4 | C79.8 | – | D21.4 | D48.1 | D49.2 |
| adipose tissue [See Also: Neoplasm, connective tissue] | C49.4 | C79.89 | – | D21.9 | D48.1 | D49.2 |
| aorta (thoracic) › abdominal | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
| connective tissue NEC › abdomen | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
| connective tissue NEC › abdominal wall | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
| connective tissue NEC › gastric | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
| connective tissue NEC › gastrointestinal | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
| connective tissue NEC › hypochondrium | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
| connective tissue NEC › intestinal | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
| connective tissue NEC › psoas muscle | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
| connective tissue NEC › stomach | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
| connective tissue NEC › umbilicus | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
| vena cava (abdominal) (inferior) | C49.4 | C79.89 | – | D21.4 | D48.1 | D49.2 |
Patient EducationClinical
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Convert C49.4 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C49.4Overview
What is the ICD-10 code for malignant neoplasm of connective and soft tissue of abdomen?
The ICD-10-CM code for malignant neoplasm of connective and soft tissue of abdomen is C49.4 (sometimes written as C494). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
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.
Is C49.4 a CC or MCC?
CMS lists C49.4 as a CC (complication or comorbidity) for FY 2026. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 2 closely related codes in its exclusion list.
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.
What HCC is C49.4?
C49.4 (malignant neoplasm of connective and soft tissue of abdomen) maps to CMS-HCC Category 23 (Prostate, Breast, and Other Cancers and Tumors), commonly written as HCC 23, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 10 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 20.
Does C49.4 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C49.4 adds a risk adjustment factor of about 0.186 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.186 to 0.237 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, HCC 20, HCC 21, and HCC 22) supersedes it when both are reported. See the full factor table on the HCC 23 category page.
