C83.18
BillableMantle cell lymphoma, lymph nodes of multiple sites
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C83.18 an HCC code?
Yes. C83.18 maps to Lung and Other Severe 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 C83.18
For C83.18 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 C83.18 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C83.18 is the ICD-10-CM diagnosis code for mantle cell lymphoma, lymph nodes of multiple sites. Mantle cell lymphoma is a type of cancer that affects white blood cells called lymphocytes and has spread to lymph nodes in multiple locations throughout the body. This is an aggressive form of non-Hodgkin lymphoma that typically affects older adults. C83.18 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, C83.18 maps to Lung and Other Severe Cancers (HCC 20) with a community, non-dual, aged base RAF weight of 0.000. Under the older CMS-HCC V24 model, C83.18 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 'multiple sites' of lymph node involvement before assigning this code; single site involvement requires a different code. Because C83.18 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 C83.18 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation specifies 'multiple sites' of lymph node involvement before assigning this code; single site involvement requires a different code
- •Ensure the histology confirms mantle cell lymphoma and document the extent of lymph node involvement to support medical necessity for treatment planning
Clinical Significance
Mantle cell lymphoma involving multiple lymph node sites indicates advanced-stage disease, which is the most common presentation for this lymphoma subtype. Approximately 70-80% of mantle cell lymphoma patients present with Stage III or IV disease. Multi-site involvement necessitates systemic therapy and carries important prognostic implications.
Documentation Requirements
- ✓Pathology-confirmed mantle cell lymphoma
- ✓Documentation of at least two distinct lymph node regions involved
- ✓Comprehensive staging with PET/CT or CT documenting all involved sites
- ✓Ann Arbor stage (typically III or IV with multi-site involvement)
- ✓MIPI prognostic score documentation