C45.2
BillableMesothelioma of pericardium
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C45.2 an HCC code?
Yes. C45.2 maps to Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model (and Lung and Other Severe Cancers under V24).
HCC Category Mapping
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 C45.2
For C45.2 to 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 C45.2 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C45.2 is the ICD-10-CM diagnosis code for mesothelioma of pericardium. A rare cancer that develops in the membrane surrounding the heart (pericardium), usually caused by asbestos exposure. C45.2 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of mesothelial and soft tissue (c45-c49).
Under the CMS-HCC V28 risk adjustment model, C45.2 maps to Lymphoma and Other Cancers (HCC 19) with a community, non-dual, aged base RAF weight of 0.105. Under the older CMS-HCC V24 model, C45.2 maps to Lung and Other Severe Cancers (HCC 9) with a community, non-dual, aged base RAF weight of 0.973. 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.
Pericardial mesothelioma is the rarest form; document any cardiac symptoms or pericardial effusion noted in clinical documentation. Because C45.2 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 C45.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Pericardial mesothelioma is the rarest form; document any cardiac symptoms or pericardial effusion noted in clinical documentation
- •Confirm the diagnosis is mesothelioma and not metastatic disease to the pericardium from another primary cancer
Clinical Significance
Mesothelioma of the pericardium is the rarest form of mesothelioma, accounting for less than 1% of all mesothelioma cases. It arises from the serosal lining of the heart and may present with pericardial effusion, constrictive pericarditis, or cardiac tamponade. Prognosis is extremely poor, with most patients surviving less than 6 months from diagnosis.
Documentation Requirements
- ✓Histologic confirmation of pericardial mesothelioma — extremely rare and requires specialized pathologic confirmation
- ✓Imaging findings (echocardiogram, CT, or cardiac MRI showing pericardial thickening or effusion)
- ✓Asbestos exposure history if present (association is weaker than pleural mesothelioma)
- ✓Cardiac functional status and hemodynamic impact
- ✓Treatment plan (pericardectomy, systemic chemotherapy, palliative care)
- ✓Distinction from metastatic pericardial disease
Excludes 1 — Do NOT code together
- other malignant neoplasm of pericardium (C38.0)
Commonly Confused Codes
- •C45.0 — Mesothelioma of pleura; different serosal surface
- •C45.1 — Mesothelioma of peritoneum; different serosal surface
- •C38.0 — Malignant neoplasm of heart; for primary cardiac tumors (sarcomas), not pericardial mesothelioma
- •C79.89 — Secondary malignant neoplasm of other specified sites; for metastatic pericardial disease