2026 ICD-10-CM Diagnosis Code C26.1Malignant neoplasm of spleen
ICD-10-CM Codes›C00–D49›C15-C26›C26
- Billable — Valid for Submission
- Risk Adjusts — HCC 22
- Chronic Condition
C26.1 is a billable ICD-10-CM diagnosis code for malignant neoplasm of spleen. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 820 through 825, 840 through 842. Coders also document this condition as angiosarcoma of spleen. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Gastrointestinal cancers - all other types.
For Medicare Advantage risk adjustment, C26.1 maps to CMS-HCC Category 22 (Bladder, Colorectal, and Other Cancers) under the V28 model, adding a risk factor of about 0.363 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C26.1 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.
- Angiosarcoma of spleen
- Fibrosarcoma
- Fibrosarcoma of spleen
- Malignant neoplasm of spleen
- Primary fibrosarcoma of spleen
- Primary malignant neoplasm of spleen
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
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
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:
- What is cancer?
- What are the types of cancer?
- How does cancer develop?
- What are the symptoms of cancer?
- How is cancer diagnosed?
- What are the treatments for cancer?
- Can cancer be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert C26.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C26.1Overview
What is the ICD-10 code for malignant neoplasm of spleen?
The ICD-10-CM code for malignant neoplasm of spleen is C26.1 (sometimes written as C261). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is C26.1 (Malignant neoplasm of other and ill-defined digestive organs) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of spleen on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C26.1 group to?
When malignant neoplasm of spleen is the principal diagnosis on an inpatient stay, it groups to MS-DRG 820, 821, 822, 823, 824, 825, 840, 841, 842, with relative weights from 1.0104 to 5.8648 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of C26.1?
Under the General Equivalence Mappings, malignant neoplasm of spleen converts to ICD-9-CM 159.1 (malignant neo spleen NEC). The mapping is a direct match.
What HCC is C26.1?
C26.1 (malignant neoplasm of spleen) maps to CMS-HCC Category 22 (Bladder, Colorectal, and Other Cancers), commonly written as HCC 22, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 11 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.
Does C26.1 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C26.1 adds a risk adjustment factor of about 0.363 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.314 to 0.410 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, HCC 20, and HCC 21) supersedes it when both are reported. See the full factor table on the HCC 22 category page.
