C83.390
BillablePrimary central nervous system lymphoma
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C83.390 an HCC code?
Yes. C83.390 maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other 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 C83.390
For C83.390to 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 C83.390 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C83.390 is the ICD-10-CM diagnosis code for primary central nervous system lymphoma. A type of aggressive blood cancer (diffuse large B-cell lymphoma) that originates in the brain or central nervous system. C83.390 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lymphoid, hematopoietic and related tissue (c81-c96).
Under the CMS-HCC V28 risk adjustment model, C83.390 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 1.136. Under the older CMS-HCC V24 model, C83.390 maps to Lymphoma and Other Cancers (HCC 10) with a community, non-dual, aged base RAF weight of 0.675. 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 CNS lymphoma is a distinct entity; ensure documentation confirms CNS origin rather than secondary involvement. Because C83.390 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 C83.390 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Primary CNS lymphoma is a distinct entity; ensure documentation confirms CNS origin rather than secondary involvement
- •Verify imaging (MRI brain) and CSF analysis results are documented to support this diagnosis
Clinical Significance
Primary central nervous system lymphoma is a rare and aggressive form of DLBCL confined to the brain, spinal cord, leptomeninges, or eyes without systemic disease. It has a distinct treatment approach (high-dose methotrexate-based regimens rather than R-CHOP) and carries a worse prognosis than systemic DLBCL, making accurate coding essential for treatment planning.
Documentation Requirements
- ✓Brain biopsy or CSF cytology/flow cytometry confirming DLBCL
- ✓MRI brain documenting CNS lesion(s)
- ✓CSF analysis results (cytology, flow cytometry, protein, glucose)
- ✓Slit-lamp examination to evaluate for vitreoretinal involvement
- ✓Complete systemic staging to confirm primary CNS origin (no systemic disease)
- ✓HIV and immunosuppression status (risk factor documentation)
Excludes 1 — Do NOT code together
Commonly Confused Codes
- •C83.398 — DLBCL, other extranodal sites; use C83.390 specifically for primary CNS lymphoma
- •C79.31 — Secondary malignant neoplasm of brain; for systemic lymphoma that has metastasized to CNS
- •C71.- — Malignant neoplasm of brain; for primary brain tumors (gliomas, etc.), not lymphoma
- •C83.30 — DLBCL, unspecified site; the CNS-specific code should always be used for primary CNS lymphoma