C81.23
BillableMixed cellularity Hodgkin lymphoma, intra-abdominal lymph nodes
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C81.23 an HCC code?
Yes. C81.23 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 C81.23
For C81.23 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 C81.23 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C81.23 is the ICD-10-CM diagnosis code for mixed cellularity hodgkin lymphoma, intra-abdominal lymph nodes. This is a type of Hodgkin lymphoma (a cancer of the lymph system) characterized by a mix of different cell types, specifically affecting the lymph nodes located in the abdomen. It represents a specific histological subtype and anatomical location of this blood cancer. C81.23 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, C81.23 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, C81.23 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 the histological subtype (mixed cellularity) is documented in the pathology report before assigning this code, as it distinguishes this from other Hodgkin lymphoma subtypes. Because C81.23 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 C81.23 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify the histological subtype (mixed cellularity) is documented in the pathology report before assigning this code, as it distinguishes this from other Hodgkin lymphoma subtypes
- •Confirm the anatomical site is specifically intra-abdominal lymph nodes; if lymph nodes in other locations are also involved, additional codes may be needed to capture all sites of disease
Clinical Significance
Mixed cellularity Hodgkin lymphoma of intra-abdominal lymph nodes indicates involvement of mesenteric, retroperitoneal, or para-aortic lymph nodes. Mixed cellularity Hodgkin lymphoma has a higher tendency for abdominal and infradiaphragmatic involvement compared to nodular sclerosis. This presentation typically reflects Stage III or higher disease and requires systemic chemotherapy. The mixed cellularity subtype's association with EBV and older patient demographics may influence treatment decisions.
Documentation Requirements
- ✓Pathology confirming mixed cellularity subtype
- ✓Cross-sectional imaging documenting abdominal lymph node involvement
- ✓Assessment of whether disease is infradiaphragmatic only or combined with supradiaphragmatic disease
- ✓Ann Arbor staging
- ✓EBV status and HIV testing
- ✓Treatment plan for advanced-stage disease