What is ICD-10 code C83.02?

C83.02 is the ICD-10-CM diagnosis code for Small cell B-cell lymphoma, intrathoracic lymph nodes. A type of cancer of the lymph system (small cell B-cell lymphoma) affecting the lymph nodes inside the chest cavity. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C83.02 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C83.02 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. C83.02 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. C83.02 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does C83.02 map to under V28?

C83.02 maps to CMS-HCC V28 HCC 21 (Lymphoma and Other Cancers). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

2026 ICD-10-CM C83.02: Small cell B-cell lymphoma

C83.02 maps to CMS-HCC V28 21. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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Code lookupC83.02

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)

C83.02

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Small cell B-cell lymphoma, intrathoracic lymph nodes

A type of cancer of the lymph system (small cell B-cell lymphoma) affecting the lymph nodes inside the chest cavity.

Buddy Insight

Small cell B-cell lymphoma involving intrathoracic lymph nodes represents a low-grade non-Hodgkin lymphoma with indolent behavior but potential for transformation to aggressive disease.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 21

Lymphoma and Other Cancers

Code-level coefficient reference

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 010

HHS-HCC 010 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 10

Lymphoma and Other Cancers

Code-level coefficient reference

RXHCC

Mapped

HCC 21

Lymphomas and Other Hematolog...

Code-level coefficient reference

Code Book Path

Official

C83Non-follicular lymphoma C83.0Small cell B-cell lymphoma C83.02Small cell B-cell lymphoma, intrathoracic lymph nodes

Inclusion Terms

Official

Lymphoplasmacytic lymphomaInherited from C83.0
Nodal marginal zone lymphomaInherited from C83.0
Non-leukemic variant of B-CLLInherited from C83.0
Splenic marginal zone lymphomaInherited from C83.0

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

Official

C83.00Small cell B-cell lymphoma, unspecified site C83.01Small cell B-cell lymphoma, lymph nodes of head, face, and neck C83.03Small cell B-cell lymphoma, intra-abdominal lymph nodes C83.04Small cell B-cell lymphoma, lymph nodes of axilla and upper limb C83.05Small cell B-cell lymphoma, lymph nodes of inguinal region and lower limb

Includes

Official

No Includes notes are included in this display for C83.02. Check the code and parent instructions in the Code Book.

Excludes 1

Official

personal history of non-Hodgkin lymphoma (Z85.72)Inherited from C83, C83.0
chronic lymphocytic leukemia (C91.1)Inherited from C83, C83.0
mature T/NK-cell lymphomas (C84.-)Inherited from C83, C83.0
Waldenström macroglobulinemia (C88.00)Inherited from C83, C83.0

Code First

Official

No Code First sequencing instructions are included in this display for C83.02. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for C83.02. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for C83.02. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Pathology-confirmed histological subtype (small cell B-cell lymphoma vs. other low-grade lymphomas)

Specific intrathoracic lymph node groups involved (mediastinal, hilar, paratracheal)

Ann Arbor staging with Cotswolds modifications

Current treatment status (active treatment, watchful waiting, post-treatment surveillance)

MEAT Support

HCC Buddy guidance

Pathology-confirmed histological subtype (small cell B-cell lymphoma vs. other low-grade lymphomas)

Specific intrathoracic lymph node groups involved (mediastinal, hilar, paratracheal)

Ann Arbor staging with Cotswolds modifications

Current treatment status (active treatment, watchful waiting, post-treatment surveillance)

Audit Caution

HCC Buddy guidance

Using unspecified site code C83.00 when imaging clearly documents intrathoracic location

Confusing small cell B-cell lymphoma with small lymphocytic lymphoma (SLL/CLL) which uses C91.1- codes

Failing to update code to C83.0A when remission is documented

Assigning extranodal code C83.09 when disease is limited to lymph nodes within the thorax

Common Mistakes

HCC Buddy guidance

C83.01 — Small cell B-cell lymphoma of head/face/neck nodes; differentiate by anatomical site documentation on imaging

C83.08 — Small cell B-cell lymphoma of multiple sites; use C83.02 only when disease is confined to intrathoracic nodes

C85.10 — Unspecified non-Hodgkin lymphoma, unspecified site; always use specific histological subtype when pathology confirms small cell B-cell

C83.12 — Mantle cell lymphoma, intrathoracic; different histological subtype requiring pathology differentiation

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 C83.02 an HCC code?

Yes. C83.02 (Small cell B-cell lymphoma, intrathoracic lymph nodes) maps to HCC 21, Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.671. 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: C83.02 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: C83.02
Description: Small cell B-cell lymphoma, intrathoracic lymph nodes
HCC (V28): HCC 21 — Lymphoma and Other Cancers
RAF reference coefficient: 0.671
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 21, Lymphoma and Other Cancers

0.671

ESRDHCC 10, Lymphoma and Other Cancers

Not separately weighted

RxHCCHCC 21, Lymphomas and Other Hematologic Cancers

Not separately weighted

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 C83.02 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C83.02

For C83.02, 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

C83.02 is the ICD-10-CM diagnosis code for small cell b-cell lymphoma, intrathoracic lymph nodes. A type of cancer of the lymph system (small cell B-cell lymphoma) affecting the lymph nodes inside the chest cavity. C83.02 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, C83.02 maps to Lymphoma and Other Cancers (HCC 21) with a source-labeled community, non-dual, aged reference coefficient of 0.671. No V24 mapping is shown for C83.02; use the applicable model and payment year when reviewing the V28 mapping. 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.

Verify documentation confirms intrathoracic (mediastinal, hilar, or other chest) lymph node involvement. For C83.02, 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 C83.02 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Verify documentation confirms intrathoracic (mediastinal, hilar, or other chest) lymph node involvement
•Cross-reference imaging reports (CT chest) to confirm the anatomical location of lymph node involvement

Clinical Significance

Small cell B-cell lymphoma involving intrathoracic lymph nodes represents a low-grade non-Hodgkin lymphoma with indolent behavior but potential for transformation to aggressive disease. Accurate site documentation is critical for staging (Ann Arbor system) and treatment planning, as intrathoracic involvement may cause mediastinal compression symptoms requiring urgent intervention.

Documentation Requirements

✓Pathology-confirmed histological subtype (small cell B-cell lymphoma vs. other low-grade lymphomas)
✓Specific intrathoracic lymph node groups involved (mediastinal, hilar, paratracheal)
✓Ann Arbor staging with Cotswolds modifications
✓Current treatment status (active treatment, watchful waiting, post-treatment surveillance)
✓Imaging confirmation (CT chest or PET/CT) documenting intrathoracic lymph node involvement

Commonly Confused Codes

•C83.01: Small cell B-cell lymphoma of head/face/neck nodes; differentiate by anatomical site documentation on imaging
•C83.08: Small cell B-cell lymphoma of multiple sites; use C83.02 only when disease is confined to intrathoracic nodes
•C85.10: Unspecified non-Hodgkin lymphoma, unspecified site; always use specific histological subtype when pathology confirms small cell B-cell
•C83.12: Mantle cell lymphoma, intrathoracic; different histological subtype requiring pathology differentiation