C86.00
BillableExtranodal NK/T-cell lymphoma, nasal type not having achieved remission
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C86.00 an HCC code?
Yes. C86.00 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 C86.00
For C86.00 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 C86.00 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C86.00 is the ICD-10-CM diagnosis code for extranodal nk/t-cell lymphoma, nasal type not having achieved remission. A rare type of lymphoma (blood cancer) that starts in the nose and nasal passages, caused by abnormal NK/T-cells that have not gone into remission. C86.00 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, C86.00 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, C86.00 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.
Verify documentation confirms active disease status and has not achieved remission. Because C86.00 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 C86.00 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation confirms active disease status and has not achieved remission
- •Distinguish from C86.01 which indicates remission status
Clinical Significance
Extranodal NK/T-cell lymphoma, nasal type is a rare, aggressive malignancy strongly associated with Epstein-Barr virus infection, predominantly affecting the nasal cavity and midline facial structures. This lymphoma is more prevalent in Asian and Latin American populations and carries a poor prognosis when not achieving remission. The destructive nature of this disease can lead to nasal septal perforation and midface deformity.
Documentation Requirements
- ✓Documentation must confirm the nasal-type extranodal NK/T-cell lymphoma diagnosis through biopsy with immunohistochemistry showing NK/T-cell markers.
- ✓Epstein-Barr virus status (EBER in situ hybridization), disease staging, extent of nasal/midface involvement, treatment approach, and confirmation that remission has not been achieved must be documented.