C84.A8 ICD-10-CM Code: Cutaneous T-cell lymphoma, unspecified, lymph nodes of multiple sites
C84.A8 maps to CMS-HCC V28 20. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools
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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)
C84.A8
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceCutaneous T-cell lymphoma, unspecified, lymph nodes of multiple sites
A type of blood cancer affecting T-cells in the skin that has spread to lymph nodes in multiple locations throughout the body.
Buddy Insight
Cutaneous T-cell lymphoma involving multiple lymph node regions indicates advanced disseminated disease with poor prognosis.
CMS-HCC V28
MappedHCC 20
Coefficient HCC 20: 1.136 (Community Non-Dual Aged (CNA))
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 010
Code-level coefficient reference
ESRD/PACE
MappedHCC 10
Code-level coefficient reference
RXHCC
MappedHCC 21
Code-level coefficient reference
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for C84.A8. Check the code and parent instructions in the Code Book.
Excludes 2
Official- Kaposi's sarcoma of lymph nodes (C46.3)Inherited from C81-C96
- secondary and unspecified neoplasm of lymph nodes (C77.-)Inherited from C81-C96
- secondary neoplasm of bone marrow (C79.52)Inherited from C81-C96
- secondary neoplasm of spleen (C78.89)Inherited from C81-C96
Related Codes
Includes
OfficialNo Includes notes are included in this display for C84.A8. Check the code and parent instructions in the Code Book.
Excludes 1
Official- personal history of non-Hodgkin lymphoma (Z85.72)Inherited from C84
Code First
OfficialNo Code First sequencing instructions are included in this display for C84.A8. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for C84.A8. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for C84.A8. Check the code and parent instructions in the Code Book.
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 C84.A8 an HCC code?
Yes. C84.A8 (Cutaneous T-cell lymphoma, unspecified, lymph nodes of multiple sites) maps to HCC 20, Lung and Other Severe Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.136. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: C84.A8 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
- C84.A8
- Description
- Cutaneous T-cell lymphoma, unspecified, lymph nodes of multiple sites
- HCC (V28)
- HCC 20 — Lung and Other Severe Cancers
- RAF reference coefficient
- 1.136
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work C84.A8 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for C84.A8
For C84.A8, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
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What This Code Means
C84.A8 is the ICD-10-CM diagnosis code for cutaneous t-cell lymphoma, unspecified, lymph nodes of multiple sites. A type of blood cancer affecting T-cells in the skin that has spread to lymph nodes in multiple locations throughout the body. C84.A8 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, C84.A8 maps to Lung and Other Severe Cancers (HCC 20) with a source-labeled community, non-dual, aged reference coefficient of 1.136. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
This code is used when cutaneous T-cell lymphoma involves multiple lymph node regions; verify documentation specifies multiple sites rather than a single site. For C84.A8, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for C84.A8 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code is used when cutaneous T-cell lymphoma involves multiple lymph node regions; verify documentation specifies multiple sites rather than a single site
- •Ensure the primary site is documented as cutaneous (skin) with secondary involvement of lymph nodes
Clinical Significance
Cutaneous T-cell lymphoma involving multiple lymph node regions indicates advanced disseminated disease with poor prognosis. Multi-site nodal involvement typically corresponds to stage III-IV disease requiring aggressive systemic treatment. This code captures the extent of lymphomatous spread essential for accurate risk stratification.
Documentation Requirements
- ✓Documentation must specify involvement of lymph nodes in at least two distinct anatomical regions
- ✓Pathology confirmation of cutaneous T-cell lymphoma subtype via skin biopsy with immunophenotyping
- ✓Imaging (CT, PET) confirming multi-site lymph node enlargement consistent with lymphomatous involvement
- ✓Clinical staging reflecting extent of nodal disease
Commonly Confused Codes
- •C84.A0 (Cutaneous T-cell lymphoma, unspecified site): Use C84.A8 when multiple lymph node regions are specifically documented
- •C84.A1 through C84.A6 (site-specific codes): Use these when only a single nodal region is involved; C84.A8 requires multiple regions
- •C84.A9 (Cutaneous T-cell lymphoma, extranodal/solid organ sites): C84.A8 is for nodal disease; C84.A9 is for disease outside lymph nodes