C90.20
BillableExtramedullary plasmacytoma not having achieved remission
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is C90.20 an HCC code?
Yes. C90.20 maps to Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model (and Lung and Other Severe 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 C90.20
For C90.20 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 C90.20 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
C90.20 is the ICD-10-CM diagnosis code for extramedullary plasmacytoma not having achieved remission. Extramedullary plasmacytoma, a tumor of plasma cells that occurs outside the bone marrow, that has not responded to treatment. C90.20 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, C90.20 maps to Lymphoma and Other Cancers (HCC 19) with a community, non-dual, aged base RAF weight of 0.105. Under the older CMS-HCC V24 model, C90.20 maps to Lung and Other Severe Cancers (HCC 9) with a community, non-dual, aged base RAF weight of 0.973. 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.
Extramedullary plasmacytoma occurs in soft tissues outside bone marrow; verify location is documented. Because C90.20 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 C90.20 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Extramedullary plasmacytoma occurs in soft tissues outside bone marrow; verify location is documented
- •Fifth character '0' indicates no remission; document the site of the tumor for complete coding
Clinical Significance
Extramedullary plasmacytoma is a solitary tumor of neoplastic plasma cells occurring outside the bone marrow, most commonly in the upper respiratory tract including the nasopharynx, paranasal sinuses, and oropharynx. Unlike multiple myeloma, it is typically a localized disease amenable to radiation therapy. Non-remission status indicates the tumor persists or has progressed despite treatment.
Documentation Requirements
- ✓Documentation must include tissue biopsy confirming a monoclonal plasma cell tumor outside the bone marrow.
- ✓The specific extramedullary site must be documented.
- ✓Imaging confirming absence of additional lesions, bone marrow biopsy excluding myeloma, serum and urine protein studies, treatment approach (typically radiation), and non-remission status are required.