What is ICD-10 code C38.0?

C38.0 is the ICD-10-CM diagnosis code for Malignant neoplasm of heart. Cancer that originates in the heart tissue itself, which is extremely rare. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C38.0 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C38.0 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. C38.0 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. C38.0 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for C38.0?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For C38.0, V28 maps to Lung and Other Severe Cancers at RAF 0.000 while V24 mapped to Colorectal, Bladder, and Other Cancers at RAF 0.306. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting C38.0?

Primary cardiac malignancies are very uncommon; verify that this is not a metastatic cancer to the heart Distinguish from pericardial cancers (C38.4) and mediastinal cancers Because C38.0 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

C38.0 ICD-10 Code: Malignant neoplasm of heart

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupC38.0Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of respiratory and intrathoracic organs (C30-C39)

C38.0

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Malignant neoplasm of heart

Cancer that originates in the heart tissue itself, which is extremely rare.

Buddy Insight

Primary cardiac malignancies are extremely rare, with cardiac sarcomas (angiosarcoma most common) being the predominant type.

CMS-HCC V28

Mapped

HCC 20

Lung and Other Severe Cancers

RAF 0.0

CMS-HCC V24

Mapped

HCC 11

Colorectal, Bladder, and Othe...

RAF 0.306

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 11

Colorectal, Bladder, and Othe...

RAF 0.0

RXHCC

Mapped

HCC 20

Cancer, Liver and Intrahepati...

RAF 0.0

Code Trumping

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Compare selected patient codes to show trumped or trumps impact.

Code Book Path

Official

C38Malignant neoplasm of heart, mediastinum and pleura

C38.0Malignant neoplasm of heart

Inclusion Terms

Official

Malignant neoplasm of pericardium

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C38.0 in this effective period.

Related Child Codes

Official

C38.1Malignant neoplasm of anterior mediastinum

C38.2Malignant neoplasm of posterior mediastinum

C38.3Malignant neoplasm of mediastinum, part unspecified

C38.4Malignant neoplasm of pleura

C38.8Malignant neoplasm of overlapping sites of heart, mediastinum and pleura

Includes

Official

ICD-10-CM does not list Includes notes for C38.0 in this effective period.

Excludes 1

Official

malignant neoplasm of great vessels (C49.3)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C38.0 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C38.0 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C38.0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathology confirmation of primary cardiac malignancy (not metastatic)

Echocardiography, cardiac MRI, or CT confirming tumor location within the heart

Histological type (angiosarcoma, rhabdomyosarcoma, fibrosarcoma, lymphoma)

Assessment of hemodynamic impact and cardiac function

MEAT Support

HCC Buddy guidance

Pathology confirmation of primary cardiac malignancy (not metastatic)

Echocardiography, cardiac MRI, or CT confirming tumor location within the heart

Histological type (angiosarcoma, rhabdomyosarcoma, fibrosarcoma, lymphoma)

Assessment of hemodynamic impact and cardiac function

Audit Caution

HCC Buddy guidance

Coding metastatic cancer involving the heart as primary cardiac cancer — the vast majority are metastatic

Confusing cardiac myxoma (benign D15.1) with primary cardiac malignancy

Not documenting whether the tumor is primary to the heart vs. pericardial vs. mediastinal with cardiac invasion

Missing hemodynamic complication codes (heart failure, arrhythmia) that often accompany cardiac tumors

Common Mistakes

HCC Buddy guidance

C79.89 — Secondary malignant neoplasm of other specified sites: Most cardiac tumors are metastatic; code as secondary if not primary

D15.1 — Benign neoplasm of heart: Cardiac myxomas are the most common cardiac tumor but are benign

C38.4 — Malignant neoplasm of pleura: Pericardial tumors may be confused with cardiac tumors

C38.1 — Anterior mediastinum: Mediastinal tumors may compress or invade the heart

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is C38.0 an HCC code?

Yes. C38.0 maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Colorectal, Bladder, and Other Cancers under V24).

HCC Category Mapping

V28HCC 20, Lung and Other Severe Cancers

0.000

V24HCC 11, Colorectal, Bladder, and Other Cancers

0.306

ESRDHCC 11, Colorectal, Bladder, and Other Cancers

0.000

RxHCCHCC 20, Cancer, Liver and Intrahepatic Bile Duct

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

MEAT Criteria for C38.0

For C38.0to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed C38.0 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

C38.0 is the ICD-10-CM diagnosis code for malignant neoplasm of heart. Cancer that originates in the heart tissue itself, which is extremely rare. C38.0 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of respiratory and intrathoracic organs (c30-c39).

Under the CMS-HCC V28 risk adjustment model, C38.0 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 0.000. Under the older CMS-HCC V24 model, C38.0 maps to Colorectal, Bladder, and Other Cancers (HCC 11) with a community, non-dual, aged base RAF weight of 0.306. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Primary cardiac malignancies are very uncommon; verify that this is not a metastatic cancer to the heart. Because C38.0 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C38.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Primary cardiac malignancies are very uncommon; verify that this is not a metastatic cancer to the heart
•Distinguish from pericardial cancers (C38.4) and mediastinal cancers

Clinical Significance

Primary cardiac malignancies are extremely rare, with cardiac sarcomas (angiosarcoma most common) being the predominant type. Most cardiac tumors are metastatic rather than primary. These patients have very poor prognosis and require complex management including cardiac surgery, making accurate distinction between primary and secondary cardiac cancer essential.

Documentation Requirements

✓Pathology confirmation of primary cardiac malignancy (not metastatic)
✓Echocardiography, cardiac MRI, or CT confirming tumor location within the heart
✓Histological type (angiosarcoma, rhabdomyosarcoma, fibrosarcoma, lymphoma)
✓Assessment of hemodynamic impact and cardiac function
✓Documentation clearly distinguishing primary from metastatic cardiac disease

Excludes 1, Do NOT code together

malignant neoplasm of great vessels (C49.3)

Commonly Confused Codes

•C79.89 — Secondary malignant neoplasm of other specified sites: Most cardiac tumors are metastatic; code as secondary if not primary
•D15.1 — Benign neoplasm of heart: Cardiac myxomas are the most common cardiac tumor but are benign
•C38.4 — Malignant neoplasm of pleura: Pericardial tumors may be confused with cardiac tumors
•C38.1 — Anterior mediastinum: Mediastinal tumors may compress or invade the heart