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C84.4A ICD-10-CM Code: Peripheral T-cell lymphoma, not elsewhere classified, in remission

C84.4A maps to CMS-HCC V28 19. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupC84.4A

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)

C84.4A

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Peripheral T-cell lymphoma, not elsewhere classified, in remission

A type of cancer affecting T-cells that is not classified elsewhere, currently in remission (no active disease detected).

Buddy the Bee presenting code insight

Buddy Insight

Peripheral T-cell lymphoma not elsewhere classified in remission indicates the patient has a history of this aggressive lymphoma but currently has no active disease.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 19

Coefficient HCC 19: 1.798 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 010

Code-level coefficient reference

ESRD/PACE

HCC 10

Code-level coefficient reference

RXHCC

HCC 21

Code-level coefficient reference

Code Book Path

Official
C84Mature T/NK-cell lymphomasC84.4Peripheral T-cell lymphoma, not elsewhere classifiedC84.4APeripheral T-cell lymphoma, not elsewhere classified, in remission

Inclusion Terms

Official
  • Lennert's lymphomaInherited from C84.4
  • Lymphoepithelioid lymphomaInherited from C84.4
  • Mature T-cell lymphoma, not elsewhere classifiedInherited from C84.4

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

Official
C84.40Peripheral T-cell lymphoma, not elsewhere classified, unspecified siteC84.41Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of head, face, and neckC84.42Peripheral T-cell lymphoma, not elsewhere classified, intrathoracic lymph nodesC84.43Peripheral T-cell lymphoma, not elsewhere classified, intra-abdominal lymph nodesC84.44Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of axilla and upper limb

Includes

Official

No Includes notes are included in this display for C84.4A. 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

Official

No Code First sequencing instructions are included in this display for C84.4A. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for C84.4A. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for C84.4A. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Original pathology confirming PTCL-NOS diagnosis
Physician statement explicitly documenting remission status (complete or partial)
Most recent imaging (PET/CT) confirming no active disease if complete remission
Documentation of ongoing surveillance schedule

MEAT Support

HCC Buddy guidance
Original pathology confirming PTCL-NOS diagnosis
Physician statement explicitly documenting remission status (complete or partial)
Most recent imaging (PET/CT) confirming no active disease if complete remission
Documentation of ongoing surveillance schedule

Audit Caution

HCC Buddy guidance
Using a site-specific active disease code when the physician has documented remission
Prematurely coding remission before the oncologist has formally documented remission status
Confusing 'no evidence of disease' on imaging with physician-documented remission — the provider must state remission
Switching to a personal history code (Z85.79) while the patient is still under active oncology surveillance for potential relapse

Common Mistakes

HCC Buddy guidance
C84.40 — PTCL-NOS, unspecified site: This is for active disease with unspecified location, NOT for remission status
Z85.79 — Personal history of other malignant neoplasms of lymphoid tissue: History code implies the cancer is resolved and no longer being monitored as an active malignancy; C84.4A implies active monitoring during remission
C84.41-C84.49 — Site-specific PTCL-NOS codes: These indicate active disease at a specific site, not remission

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 C84.4A an HCC code?

Yes. C84.4A (Peripheral T-cell lymphoma, not elsewhere classified, in remission) maps to HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.798. 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: C84.4A is billable and maps to V28 HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
C84.4A
Description
Peripheral T-cell lymphoma, not elsewhere classified, in remission
HCC (V28)
HCC 19 — Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers
RAF reference coefficient
1.798
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers
1.798
ESRDHCC 10, Lymphoma and Other Cancers
Not separately weighted
RxHCCHCC 21, Lymphomas and Other Hematologic Cancers
Not separately weighted

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 C84.4A in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C84.4A

For C84.4A, 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

C84.4A is the ICD-10-CM diagnosis code for peripheral t-cell lymphoma, not elsewhere classified, in remission. A type of cancer affecting T-cells that is not classified elsewhere, currently in remission (no active disease detected). C84.4A 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, C84.4A maps to Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers (HCC 19) with a source-labeled community, non-dual, aged reference coefficient of 1.798. No V24 mapping is shown for C84.4A; use the applicable model and payment year when reviewing the V28 mapping. 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.

Only use this code when documentation explicitly states remission status. For C84.4A, 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 C84.4A sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Only use this code when documentation explicitly states remission status
  • •Verify the remission is complete or partial as documented by the physician

Clinical Significance

Peripheral T-cell lymphoma not elsewhere classified in remission indicates the patient has a history of this aggressive lymphoma but currently has no active disease. Remission status is clinically significant because PTCL-NOS has high relapse rates, requiring ongoing surveillance. This code maintains the cancer diagnosis for risk adjustment while accurately reflecting current disease status.

Documentation Requirements

  • ✓Original pathology confirming PTCL-NOS diagnosis
  • ✓Physician statement explicitly documenting remission status (complete or partial)
  • ✓Most recent imaging (PET/CT) confirming no active disease if complete remission
  • ✓Documentation of ongoing surveillance schedule
  • ✓Treatment history including chemotherapy regimen completed

Commonly Confused Codes

  • •C84.40: PTCL-NOS, unspecified site: This is for active disease with unspecified location, NOT for remission status
  • •Z85.79: Personal history of other malignant neoplasms of lymphoid tissue: History code implies the cancer is resolved and no longer being monitored as an active malignancy; C84.4A implies active monitoring during remission
  • •C84.41-C84.49: Site-specific PTCL-NOS codes: These indicate active disease at a specific site, not remission

Child Codes

C84.40Peripheral T-cell lymphoma, not elsewhere classified, unspecified site
HCC 19
C84.41Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of head, face, and neck
HCC 19
C84.42Peripheral T-cell lymphoma, not elsewhere classified, intrathoracic lymph nodes
HCC 19
C84.43Peripheral T-cell lymphoma, not elsewhere classified, intra-abdominal lymph nodes
HCC 19
C84.44Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of axilla and upper limb
HCC 19
C84.45Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of inguinal region and lower limb
HCC 19
C84.46Peripheral T-cell lymphoma, not elsewhere classified, intrapelvic lymph nodes
HCC 19
C84.47Peripheral T-cell lymphoma, not elsewhere classified, spleen
HCC 19
C84.48Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of multiple sites
HCC 19
C84.49Peripheral T-cell lymphoma, not elsewhere classified, extranodal and solid organ sites
HCC 19
C84.4APeripheral T-cell lymphoma, not elsewhere classified, in remission
HCC 19

Code Hierarchy

└C84Mature T/NK-cell lymphomas└C84.4Peripheral T-cell lymphoma, not elsewhere classified└C84.4APeripheral T-cell lymphoma, not elsewhere classified, in remission
└C84.4APeripheral T-cell lymphoma, not elsewhere classified, in remission

C84.4A code history

Code setChange
FY2025 (effective Oct 1, 2024)Added to the code set

Source: official CMS ICD-10-CM order and addenda files, FY2016 through FY2027.

Also searched as

  • C84 4A
  • C844A

For C84.4A, 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.

C84.4A maps to CMS-HCC V28 category 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for C84.4A. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

Work C84.4A in HCC Buddy

Open C84.4A in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

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