C82.51
BillableDiffuse follicle center lymphoma, 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 C82.51 an HCC code?
Yes. C82.51 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors 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 C82.51
For C82.51 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 C82.51 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C82.51 is the ICD-10-CM diagnosis code for diffuse follicle center lymphoma, lymph nodes of head, face, and neck. A type of cancer of the lymph system (diffuse follicle center lymphoma) located in the lymph nodes of the head, face, and neck area. C82.51 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, C82.51 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors (HCC 21) with a community, non-dual, aged base RAF weight of 0.545. Under the older CMS-HCC V24 model, C82.51 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.
Verify documentation specifies head, face, and neck involvement versus other sites. Because C82.51 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 C82.51 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation specifies head, face, and neck involvement versus other sites
- •Head and neck involvement may affect treatment planning and prognosis differently than other sites
Clinical Significance
Diffuse follicle center lymphoma involving head, face, and neck lymph nodes represents a localized presentation that may offer a more favorable prognosis if limited to a single nodal region (stage I-II). Head and neck lymphadenopathy from lymphoma requires differentiation from the much more common reactive lymphadenopathy and other head and neck malignancies. Early-stage disease in this region may be amenable to involved-field radiation therapy.
Documentation Requirements
- ✓Pathology confirming diffuse follicle center lymphoma histology
- ✓Specific identification of which head, face, or neck lymph nodes are involved (cervical, submandibular, preauricular, etc.)
- ✓Imaging (CT or PET/CT) documenting the extent of disease in the head and neck region
- ✓Documentation of whether disease is limited to head/neck or involves other regions
- ✓Biopsy results with immunophenotyping