2026 ICD-10-CM Diagnosis Code C38.0Malignant neoplasm of heart
ICD-10-CM Codes›C00–D49›C30-C39›C38
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 20
- Chronic Condition
C38.0 is a billable ICD-10-CM diagnosis code for malignant neoplasm of heart. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 314 through 316. 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 Cardiac cancers.
For Medicare Advantage risk adjustment, C38.0 maps to CMS-HCC Category 20 (Lung and Other Severe Cancers) under the V28 model, adding a risk factor of about 1.136 for a community, non-dual, aged beneficiary in payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
C38.0 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.
- Malignant germ cell neoplasm of heart
- Malignant germ cell neoplasm of mediastinum
- Malignant neoplasm of endocardium
- Malignant neoplasm of heart
- Malignant neoplasm of myocardium
- Malignant neoplasm of pericardium
- Neoplasm of endocardium
- Neoplasm of epicardium
- Neoplasm of myocardium
- Primary angiosarcoma of heart
- Primary angiosarcoma of thorax
- Primary angiosarcoma of trunk
- Primary malignant neoplasm of endocardium
- Primary malignant neoplasm of epicardium
- Primary malignant neoplasm of heart
- Primary malignant neoplasm of myocardium
- Primary malignant neoplasm of pericardium
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Malignant neoplasm of pericardium
Type 1 Excludes
- malignant neoplasm of great vessels C49.3
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.
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
Endocardium
the innermost layer of the heart, comprised of endothelial cells.Myocardial Stunning
prolonged dysfunction of the myocardium after a brief episode of severe ischemia, with gradual return of contractile activity.Myocardium
the muscle tissue of the heart. it is composed of striated, involuntary muscle cells (myocytes, cardiac) connected to form the contractile pump to generate blood flow.Pericardial Fluid
watery fluid produced in the serous and visceral pericardium surrounding the surface of the heart.Pericardium
a conical fibro-serous sac surrounding the heart and the roots of the great vessels (aorta; venae cavae; pulmonary artery). pericardium consists of two sacs: the outer fibrous pericardium and the inner serous pericardium. the latter consists of an outer parietal layer facing the fibrous pericardium, and an inner visceral layer (epicardium) resting next to the heart, and a pericardial cavity between these two layers.
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. |
|---|---|---|---|---|---|---|
| atrium, cardiac | C38.0 | C79.89 | – | D15.1 | D48.7 | D49.89 |
| endocardium | C38.0 | C79.89 | – | D15.1 | D48.7 | D49.89 |
| epicardium | C38.0 | C79.89 | – | D15.1 | D48.7 | D49.89 |
| heart | C38.0 | C79.89 | – | D15.1 | D48.7 | D49.89 |
| myocardium | C38.0 | C79.89 | – | D15.1 | D48.7 | D49.89 |
| myopericardium | C38.0 | C79.89 | – | D15.1 | D48.7 | D49.89 |
| pericardium | C38.0 | C79.89 | – | D15.1 | D48.7 | D49.89 |
| ventricle (cerebral) (floor) (lateral) (third) › cardiac (left) (right) | C38.0 | C79.89 | – | D15.1 | D48.7 | D49.89 |
Patient EducationClinical
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Convert C38.0 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C38.0Overview
What is the ICD-10 code for malignant neoplasm of heart?
The ICD-10-CM code for malignant neoplasm of heart is C38.0 (sometimes written as C380). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is C38.0 (Malignant neoplasm of heart, mediastinum and pleura) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of heart on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C38.0 group to?
When malignant neoplasm of heart is the principal diagnosis on an inpatient stay, it groups to MS-DRG 314, 315, 316, with relative weights from 0.6821 to 2.0852 depending on complications. Higher weights mean higher Medicare reimbursement.
Is C38.0 a CC or MCC?
CMS lists C38.0 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 C38.0?
Under the General Equivalence Mappings, malignant neoplasm of heart converts to ICD-9-CM 164.1 (malignant neopl heart). The mapping is approximate, so confirm the match fits the documentation.
What HCC is C38.0?
C38.0 (malignant neoplasm of heart) maps to CMS-HCC Category 20 (Lung and Other Severe Cancers), commonly written as HCC 20, 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. In the Part D prescription drug model it maps to RxHCC 20.
Does C38.0 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C38.0 adds a risk adjustment factor of about 1.136 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.672 to 1.214 depending on the payment segment). A more severe related category (HCC 17, HCC 18, and HCC 19) supersedes it when both are reported. See the full factor table on the HCC 20 category page.
