C90.32 ICD-10-CM Code: Solitary plasmacytoma in relapse
C90.32 maps to CMS-HCC V28 19. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software
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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)
C90.32
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceSolitary plasmacytoma in relapse
A single tumor made of plasma cells that has returned after a period of remission.
Buddy Insight
Solitary plasmacytoma in relapse indicates recurrence of the bone lesion after achieving remission, which may occur at the original site or as a new solitary bone lesion.
CMS-HCC V28
MappedHCC 19
Coefficient HCC 19: 1.798 (Community Non-Dual Aged (CNA))
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 010
Code-level coefficient reference
ESRD/PACE
MappedHCC 10
Code-level coefficient reference
RXHCC
MappedHCC 16
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Localized malignant plasma cell tumor NOSInherited from C90.3
- Plasmacytoma NOSInherited from C90.3
- Solitary myelomaInherited from C90.3
Excludes 2
Official- Kaposi's sarcoma of lymph nodes (C46.3)Inherited from C81-C96
- secondary and unspecified neoplasm of lymph nodes (C77.-)Inherited from C81-C96
- secondary neoplasm of bone marrow (C79.52)Inherited from C81-C96
- secondary neoplasm of spleen (C78.89)Inherited from C81-C96
Related Codes
Includes
OfficialNo Includes notes are included in this display for C90.32. Check the code and parent instructions in the Code Book.
Excludes 1
Official- personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues (Z85.79)Inherited from C90
Code First
OfficialNo Code First sequencing instructions are included in this display for C90.32. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for C90.32. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for C90.32. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is C90.32 an HCC code?
Yes. C90.32 (Solitary plasmacytoma in relapse) maps to HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.798. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: C90.32 is billable and maps to V28 HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- C90.32
- Description
- Solitary plasmacytoma in relapse
- HCC (V28)
- HCC 19 — Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers
- RAF reference coefficient
- 1.798
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work C90.32 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for C90.32
For C90.32, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- 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
Coder workflow notes
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What This Code Means
C90.32 is the ICD-10-CM diagnosis code for solitary plasmacytoma in relapse. A single tumor made of plasma cells that has returned after a period of remission. C90.32 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, C90.32 maps to Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers (HCC 19) with a source-labeled community, non-dual, aged reference coefficient of 1.798. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
Use C90.32 when the provider wording supports solitary plasmacytoma in relapse. Check the FY2026 tabular notes and the full code path before the final code choice. For C90.32, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for C90.32 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use C90.32 when the provider wording supports solitary plasmacytoma in relapse. Check the FY2026 tabular notes and the full code path before the final code choice.
- •For this DOS, capture the provider's current assessment and the care action documented for solitary plasmacytoma in relapse. Keep the checklist tied to the note.
- •Do not swap C90.32 with C90.30. The FY2026 tabular describes C90.30 as solitary plasmacytoma not having achieved remission. Follow the documented detail.
- •C90.32 maps to V28 HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers. The mapping does not replace the documentation review. The code still has to match the note.
- •Ask Buddy to show the official notes for C90.32 or compare its code path with C90.30.
Clinical Significance
Solitary plasmacytoma in relapse indicates recurrence of the bone lesion after achieving remission, which may occur at the original site or as a new solitary bone lesion. Relapse is a critical juncture as it significantly increases the likelihood of progression to systemic multiple myeloma. Comprehensive restaging is essential to determine whether the disease remains solitary or has evolved into multiple myeloma.
Documentation Requirements
- ✓Documentation must show evidence of recurrence after documented remission, with imaging confirming the relapsed lesion.
- ✓Complete restaging including bone marrow biopsy, skeletal survey or PET-CT, and serum and urine protein studies must be performed to exclude myeloma evolution.
- ✓New treatment plan and disease burden assessment must be recorded.
Commonly Confused Codes
- •C90.30 (solitary plasmacytoma not in remission) is for initial non-response.
- •C90.31 (solitary plasmacytoma in remission) indicates no recurrence.
- •C90.02 (multiple myeloma in relapse) should be used if restaging reveals systemic disease.
- •C90.20 (extramedullary plasmacytoma) applies to soft tissue relapse.