C86.1 ICD-10-CM Code: Hepatosplenic T-cell lymphoma
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)
C86.1
Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidanceHepatosplenic T-cell lymphoma
Hepatosplenic T-cell lymphoma
CMS-HCC V28
00
RAF 0
CMS-HCC V24
MappedHCC 10
RAF 0.675
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
00
RAF 0
Code Trumping
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Code Book Path
Inclusion Terms
Official- Alpha-beta and gamma delta types
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for C86.1 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for C86.1 in this effective period.
Excludes 1
Official- anaplastic large cell lymphoma, ALK negative (C84.7-)
- anaplastic large cell lymphoma, ALK positive (C84.6-)
- mature T/NK-cell lymphomas (C84.-)
- other specified types of non-Hodgkin lymphoma (C85.8-)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for C86.1 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for C86.1 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for C86.1 in this effective period.
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 C86.1 an HCC code?
Yes. C86.1 maps to Lymphoma and Other Cancers under the V24 model but is not retained in V28.
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 C86.1
For C86.1to 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 C86.1 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
C86.1 is the ICD-10-CM diagnosis code for hepatosplenic t-cell lymphoma. C86.1 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 older CMS-HCC V24 model, C86.1 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.
Header codes like C86.1 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at C86.1's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for C86.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.