C86.00 ICD-10-CM Code: Extranodal NK/T-cell lymphoma, nasal type not having achieved remission
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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)
C86.00
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceExtranodal 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.
Buddy Insight
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.
CMS-HCC V28
MappedHCC 20
RAF 1.136
CMS-HCC V24
MappedHCC 10
RAF 0.675
ACA/HHS
MappedHCC 10
Varies by metal level
ESRD/PACE
MappedHCC 10
RAF 0.111
RXHCC
MappedHCC 21
RAF 0.410
Code Book Path
Inclusion Terms
Official- Extranodal NK/T-cell lymphoma, nasal type NOS
- Extranodal NK/T-cell lymphoma, nasal type with failed remission
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for C86.00 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for C86.00 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for C86.00 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for C86.00 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for C86.00 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for C86.00 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is C86.00 an HCC code?
Yes. C86.00 (Extranodal NK/T-cell lymphoma, nasal type not having achieved remission) maps to Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24), with a community non-dual aged RAF of 1.136. It is billable for payment year 2026.
Coder answer: C86.00 is billable and maps to V28 HCC 20, Lung and Other Severe Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- C86.00
- Description
- Extranodal NK/T-cell lymphoma, nasal type not having achieved remission
- HCC (V28)
- HCC 20 — Lung and Other Severe Cancers
- RAF
- 1.136
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. 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.
Work C86.00 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
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.
Coder workflow notes
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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 1.136. 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.
Commonly Confused Codes
- •C86.01 (same lymphoma in remission) requires documented remission status.
- •C85.90 (NHL unspecified) is less specific and should not be used when NK/T-cell nasal type is confirmed.
- •C31.0 (malignant neoplasm of maxillary sinus) and other sinonasal carcinoma codes apply to epithelial tumors, not lymphomas.