What is ICD-10 code C84.44?

C84.44 is the ICD-10-CM diagnosis code for Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of axilla and upper limb. A type of T-cell lymphoma affecting the lymph nodes in the armpits and upper arms. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C84.44 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C84.44 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. C84.44 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. C84.44 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does C84.44 map to under V28?

C84.44 maps to CMS-HCC V28 HCC 19 (Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

2026 ICD-10-CM C84.44: Peripheral T-cell lymphoma

C84.44 maps to CMS-HCC V28 19. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · HCC coding software

ICD-10-CM Code View

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Code lookupC84.44Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

C84.44

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

Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of axilla and upper limb

A type of T-cell lymphoma affecting the lymph nodes in the armpits and upper arms.

Buddy Insight

Peripheral T-cell lymphoma not elsewhere classified involving axillary and upper limb lymph nodes represents an aggressive lymphoma with peripheral nodal disease.

CMS-HCC V28

Mapped

HCC 19

Myelodysplastic Syndromes, Mu...

Code-level coefficient reference

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 010

HHS-HCC 010 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 10

Lymphoma and Other Cancers

Code-level coefficient reference

RXHCC

Mapped

HCC 21

Lymphomas and Other Hematolog...

Code-level coefficient reference

Code Book Path

Official

C84Mature T/NK-cell lymphomas

C84.4Peripheral T-cell lymphoma, not elsewhere classified

C84.44Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of axilla and upper limb

Inclusion Terms

Official

Lennert's lymphoma
Lymphoepithelioid lymphoma
Mature T-cell lymphoma, not elsewhere classified

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C84.44 in this effective period.

Related Child Codes

Official

C84.40Peripheral T-cell lymphoma, not elsewhere classified, unspecified site

C84.41Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of head, face, and neck

C84.42Peripheral T-cell lymphoma, not elsewhere classified, intrathoracic lymph nodes

C84.43Peripheral T-cell lymphoma, not elsewhere classified, intra-abdominal lymph nodes

C84.45Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of inguinal region and lower limb

Includes

Official

ICD-10-CM does not list Includes notes for C84.44 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C84.44 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C84.44 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C84.44 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C84.44 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathology report confirming PTCL-NOS with T-cell immunophenotype

Physical examination or imaging confirming axillary and/or upper limb lymph node enlargement

Immunohistochemistry panel excluding specific T-cell lymphoma subtypes

Ann Arbor clinical staging

MEAT Support

HCC Buddy guidance

Pathology report confirming PTCL-NOS with T-cell immunophenotype

Physical examination or imaging confirming axillary and/or upper limb lymph node enlargement

Immunohistochemistry panel excluding specific T-cell lymphoma subtypes

Ann Arbor clinical staging

Audit Caution

HCC Buddy guidance

Coding reactive lymphadenopathy as lymphoma without pathologic confirmation

Failing to specify axillary/upper limb site when imaging clearly identifies the location, defaulting to unspecified C84.40

Not updating the site code when disease extends beyond axillary nodes to additional regions

Confusing PTCL-NOS with anaplastic large cell lymphoma when both present as large cell proliferations in axillary nodes

Common Mistakes

HCC Buddy guidance

C84.64 — Anaplastic large cell lymphoma, ALK-positive, axilla/upper limb: ALCL ALK+ has specific pathologic features (hallmark cells, ALK expression) and better prognosis than PTCL-NOS

C84.74 — Anaplastic large cell lymphoma, ALK-negative, axilla/upper limb: ALK-negative ALCL is a separate entity with distinct morphology

C83.34 — Diffuse large B-cell lymphoma, axilla/upper limb: B-cell lineage must be excluded; DLBCL is the most common large cell lymphoma and can mimic PTCL-NOS clinically

C84.48 — PTCL-NOS, multiple sites: Use C84.44 only when disease is limited to axillary/upper limb nodes

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 C84.44 an HCC code?

Yes. C84.44 (Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of axilla and upper limb) 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: C84.44 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: C84.44
Description: Peripheral T-cell lymphoma, not elsewhere classified, lymph nodes of axilla and upper limb
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 C84.44 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for C84.44

For C84.44 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 C84.44 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C84.44 is the ICD-10-CM diagnosis code for peripheral t-cell lymphoma, not elsewhere classified, lymph nodes of axilla and upper limb. A type of T-cell lymphoma affecting the lymph nodes in the armpits and upper arms. C84.44 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, C84.44 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 C84.44; use the applicable model and payment year when reviewing the V28 mapping. 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. 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.

Verify documentation confirms axillary or upper limb lymph node involvement. Because C84.44 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. 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 C84.44 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Verify documentation confirms axillary or upper limb lymph node involvement
•This includes lymph nodes of the shoulder and upper extremity

Clinical Significance

Peripheral T-cell lymphoma not elsewhere classified involving axillary and upper limb lymph nodes represents an aggressive lymphoma with peripheral nodal disease. Axillary lymphadenopathy from T-cell lymphoma must be differentiated from reactive lymphadenopathy, metastatic solid tumors, and B-cell lymphomas. Accurate coding supports proper staging and prognostic stratification.

Documentation Requirements

✓Pathology report confirming PTCL-NOS with T-cell immunophenotype
✓Physical examination or imaging confirming axillary and/or upper limb lymph node enlargement
✓Immunohistochemistry panel excluding specific T-cell lymphoma subtypes
✓Ann Arbor clinical staging
✓Documentation of active disease status

Commonly Confused Codes

•C84.64: Anaplastic large cell lymphoma, ALK-positive, axilla/upper limb: ALCL ALK+ has specific pathologic features (hallmark cells, ALK expression) and better prognosis than PTCL-NOS
•C84.74: Anaplastic large cell lymphoma, ALK-negative, axilla/upper limb: ALK-negative ALCL is a separate entity with distinct morphology
•C83.34: Diffuse large B-cell lymphoma, axilla/upper limb: B-cell lineage must be excluded; DLBCL is the most common large cell lymphoma and can mimic PTCL-NOS clinically
•C84.48: PTCL-NOS, multiple sites: Use C84.44 only when disease is limited to axillary/upper limb nodes