2026 ICD-10-CM Diagnosis Code C49.8Malignant neoplasm of overlapping sites of connective and soft tissue
ICD-10-CM Codes›C00–D49›C45-C49›C49
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 21
- Chronic Condition
C49.8 is a billable ICD-10-CM diagnosis code for malignant neoplasm of overlapping sites of connective and soft tissue. 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. Coders also document this condition as overlapping malignant neoplasm of soft tissues. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Sarcoma.
For Medicare Advantage risk adjustment, C49.8 maps to CMS-HCC Category 21 (Lymphoma and Other Cancers) under the V28 model, adding a risk factor of about 0.671 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C49.8 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.
- Overlapping malignant neoplasm of soft tissues
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Primary malignant neoplasm of two or more contiguous sites of connective and soft tissue
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.
Table of NeoplasmsClinical
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.
The full article covers:
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- How does cancer develop?
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Read the full article at MedlinePlus
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Convert C49.8 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C49.8Overview
What is the ICD-10 code for malignant neoplasm of overlapping sites of connective and soft tissue?
The ICD-10-CM code for malignant neoplasm of overlapping sites of connective and soft tissue is C49.8 (sometimes written as C498). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is C49.8 (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 overlapping sites of connective and soft tissue on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C49.8 group to?
When malignant neoplasm of overlapping sites of connective and soft tissue 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 C49.8 a CC or MCC?
CMS lists C49.8 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 C49.8?
Under the General Equivalence Mappings, malignant neoplasm of overlapping sites of connective and soft tissue converts to ICD-9-CM 171.8 (mal neo soft tissue NEC). The mapping is approximate, so confirm the match fits the documentation.
What HCC is C49.8?
C49.8 (malignant neoplasm of overlapping sites of connective and soft tissue) maps to CMS-HCC Category 21 (Lymphoma and Other Cancers), commonly written as HCC 21, 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 22.
Does C49.8 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C49.8 adds a risk adjustment factor of about 0.671 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.493 to 0.739 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, and HCC 20) supersedes it when both are reported. See the full factor table on the HCC 21 category page.
