C90.12 ICD-10-CM Code: Plasma cell leukemia in relapse
HCC Buddy Code Card
Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.
FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)
C90.12
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidancePlasma cell leukemia in relapse
Plasma cell leukemia that has returned or worsened after a period of remission.
Buddy Insight
Plasma cell leukemia in relapse indicates this highly aggressive plasma cell neoplasm has recurred after achieving remission.
CMS-HCC V28
MappedHCC 19
RAF 0.105
CMS-HCC V24
MappedHCC 9
RAF 0.973
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 9
RAF 0.0
RXHCC
MappedHCC 16
RAF 0.0
Code Trumping
Basket needed
Code Book Path
Inclusion Terms
Official- Plasmacytic leukemia
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for C90.12 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for C90.12 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for C90.12 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for C90.12 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for C90.12 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for C90.12 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is C90.12 an HCC code?
Yes. C90.12 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 C90.12
For C90.12to 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 C90.12 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
C90.12 is the ICD-10-CM diagnosis code for plasma cell leukemia in relapse. Plasma cell leukemia that has returned or worsened after a period of remission. C90.12 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, C90.12 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, C90.12 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.
Fifth character '2' indicates relapse; document the timeline from initial remission to relapse. Because C90.12 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 C90.12 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Fifth character '2' indicates relapse; document the timeline from initial remission to relapse
- •Relapsed plasma cell leukemia typically requires change in treatment approach; note current therapy
Clinical Significance
Plasma cell leukemia in relapse indicates this highly aggressive plasma cell neoplasm has recurred after achieving remission. Relapsed plasma cell leukemia has an extremely poor prognosis with limited treatment options. Secondary plasma cell leukemia arising from relapsed multiple myeloma represents one of the most treatment-resistant hematologic malignancies.
Documentation Requirements
- ✓Documentation must demonstrate recurrence of circulating plasma cells meeting diagnostic thresholds after a documented period of remission.
- ✓Prior treatment history, remission duration, current peripheral blood and bone marrow findings, new treatment plan, and relapse designation must be recorded.