C88.40 ICD-10-CM Code: Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma] not having achieved remission
C88.40 maps to CMS-HCC V28 21 (RAF 0.671). Documentation must support MEAT. 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)
C88.40
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceExtranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma] not having achieved remission
A type of lymphoma affecting mucous membranes and associated lymphoid tissue (such as stomach or salivary glands) that has not responded adequately to treatment.
Buddy Insight
Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is the most common type of marginal zone lymphoma, frequently arising in the stomach in association with Helicobacter pylori infection.
CMS-HCC V28
MappedHCC 21
RAF 0.671
CMS-HCC V24
MappedHCC 10
RAF 0.675
ACA/HHS
MappedHCC 10
Varies by metal level
ESRD/PACE
MappedHCC 10
RAF 0.111
RXHCC
MappedHCC 21
RAF 0.410
Code Book Path
Inclusion Terms
Official- Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma] NOS
- Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma] with failed remission
- Lymphoma of bronchial-associated lymphoid tissue [BALT-lymphoma] NOS
- Lymphoma of bronchial-associated lymphoid tissue [BALT-lymphoma] not having achieved remission
- Lymphoma of bronchial-associated lymphoid tissue [BALT-lymphoma] with failed remission
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for C88.40 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for C88.40 in this effective period.
Excludes 1
Official- high malignant (diffuse large B-cell) lymphoma (C83.3-)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for C88.40 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for C88.40 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for C88.40 in this effective period.
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 C88.40 an HCC code?
Yes. C88.40 (Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma] not having achieved remission) maps to Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model (and Lymphoma and Other Cancers under V24), with a community non-dual aged RAF of 0.671. It is billable for payment year 2026.
Coder answer: C88.40 is billable and maps to V28 HCC 21, Lymphoma and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- C88.40
- Description
- Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma] not having achieved remission
- HCC (V28)
- HCC 21 — Lymphoma and Other Cancers
- RAF
- 0.671
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
Each model's RAF is its CMS base weight for that model's standard population, so 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 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.
Work C88.40 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for C88.40
For C88.40 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 C88.40 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
C88.40 is the ICD-10-CM diagnosis code for extranodal marginal zone b-cell lymphoma of mucosa-associated lymphoid tissue [malt-lymphoma] not having achieved remission. A type of lymphoma affecting mucous membranes and associated lymphoid tissue (such as stomach or salivary glands) that has not responded adequately to treatment. C88.40 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, C88.40 maps to Lymphoma and Other Cancers (HCC 21) with a community, non-dual, aged base RAF weight of 0.671. Under the older V24 model, C88.40 mapped to the same category but with a base RAF weight of 0.675, V28 recalibrated weights across the entire model. 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.
Use C88.40 when the provider wording supports extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma] not having achieved remission. Check the FY2026 tabular notes and the full code path before the final code choice. Because C88.40 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 C88.40 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use C88.40 when the provider wording supports extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma] not having achieved remission. 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 extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma] not having achieved remission. Keep the checklist tied to the note.
- •Do not swap C88.40 with C88.41. The FY2026 tabular describes C88.41 as extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue [MALT-lymphoma], in remission. Follow the documented detail.
- •C88.40 maps to V28 HCC 21, Lymphoma 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 C88.40 or compare its code path with C88.41.
Clinical Significance
Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is the most common type of marginal zone lymphoma, frequently arising in the stomach in association with Helicobacter pylori infection. Other common sites include the salivary glands, thyroid, ocular adnexa, and lungs, each with distinct etiologies. Non-remission status indicates the lymphoma persists despite treatment, which may include Helicobacter pylori eradication or chemotherapy.
Documentation Requirements
- ✓Documentation must include biopsy with immunohistochemistry confirming marginal zone B-cell lymphoma involving mucosal tissue.
- ✓The specific anatomical site, Helicobacter pylori status (particularly for gastric MALT), staging workup, treatment approach, eradication therapy results, and non-remission status must be documented.
Commonly Confused Codes
- •C88.41 (MALT lymphoma in remission) requires documented remission.
- •C83.00-C83.09 (small cell B-cell lymphoma) is a different B-cell lymphoma subtype.
- •C16.x (malignant neoplasm of stomach) applies to gastric carcinoma, not lymphoma.
- •C88.30 (immunoproliferative small intestinal disease) is a related but distinct entity.