C84.41
BillablePeripheral T-cell lymphoma, not elsewhere classified, lymph nodes of head, face, and neck
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C84.41 an HCC code?
Yes. C84.41 maps to Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24).
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 C84.41
For C84.41 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 C84.41 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C84.41 is the ICD-10-CM diagnosis code for peripheral t-cell lymphoma, not elsewhere classified, lymph nodes of head, face, and neck. A type of T-cell lymphoma affecting the lymph nodes in the head, face, and neck region. C84.41 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, C84.41 maps to Lymphoma and Other Cancers (HCC 19) with a community, non-dual, aged base RAF weight of 0.105. Under the older V24 model, C84.41 mapped to the same category but with a base RAF weight of 0.675 — V28 recalibrated weights across the entire model. 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.
Confirm documentation specifies involvement of head, face, or neck lymph nodes. Because C84.41 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 C84.41 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm documentation specifies involvement of head, face, or neck lymph nodes
- •This code is site-specific; do not use if involvement is in other lymph node regions
Clinical Significance
Peripheral T-cell lymphoma, not elsewhere classified, involving lymph nodes of the head, face, and neck indicates this aggressive T-cell malignancy has been localized to cervical, preauricular, or other head/neck lymph nodes. Site-specific coding supports accurate staging and treatment planning. Head and neck presentations may be detected earlier due to visible or palpable lymphadenopathy, potentially allowing for earlier intervention.
Documentation Requirements
- ✓Pathology confirming peripheral T-cell lymphoma with T-cell markers on immunohistochemistry
- ✓Documentation confirming head, face, or neck lymph node involvement
- ✓Imaging (CT or PET/CT) of the head and neck region
- ✓Staging documentation
- ✓Treatment plan — systemic therapy typically required even for localized disease
Commonly Confused Codes
- •C84.01 — Mycosis fungoides, head/face/neck: Cutaneous T-cell lymphoma distinct from peripheral T-cell lymphoma
- •C84.11 — Sezary disease, head/face/neck: Leukemic cutaneous T-cell lymphoma, different entity
- •C83.91 — Non-follicular lymphoma, unspecified, head/face/neck: B-cell or unspecified lineage; verify T-cell markers
- •C84.40 — Peripheral T-cell lymphoma, unspecified site: Use C84.41 when head/face/neck involvement is confirmed