C85.15
BillableUnspecified B-cell lymphoma, lymph nodes of inguinal region and lower limb
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C85.15 an HCC code?
Yes. C85.15 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 C85.15
For C85.15 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 C85.15 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C85.15 is the ICD-10-CM diagnosis code for unspecified b-cell lymphoma, lymph nodes of inguinal region and lower limb. A cancer of B-cells located in the lymph nodes of the groin area and lower leg. C85.15 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, C85.15 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, C85.15 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.
Confirm documentation indicates inguinal region or lower limb lymph node involvement. Because C85.15 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 C85.15 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm documentation indicates inguinal region or lower limb lymph node involvement
- •This includes groin nodes and nodes in the lower extremities
Clinical Significance
Unspecified B-cell lymphoma involving lymph nodes of inguinal region and lower limb identifies the anatomical location but lacks specific subtype classification. B-cell lymphoma subtype determination (diffuse large B-cell, follicular, mantle cell, marginal zone, etc.) is critical for treatment selection and prognosis. While the site specificity is valuable, coders should always query for the B-cell subtype from pathology before accepting this code.
Documentation Requirements
- ✓Pathology with immunophenotyping confirming B-cell lineage (CD20, CD19, PAX5 markers)
- ✓Clinical or imaging documentation confirming involvement of lymph nodes of inguinal region and lower limb
- ✓Query provider for specific B-cell lymphoma subtype if pathology report is available
- ✓Staging information including Ann Arbor stage, B-symptoms, and performance status