What is ICD-10 code C82.12?

C82.12 is the ICD-10-CM diagnosis code for Follicular lymphoma grade II, intrathoracic lymph nodes. A slow-growing cancer of lymph cells (follicular lymphoma, grade II) affecting lymph nodes in the chest area. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C82.12 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C82.12 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. C82.12 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. C82.12 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 C82.12 map to under V28?

C82.12 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 C82.12: Follicular lymphoma grade

C82.12 maps to CMS-HCC V28 21. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · HCC Buddy coding tools

ICD-10-CM Code View

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Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupC82.12Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

C82.12

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

Follicular lymphoma grade II, intrathoracic lymph nodes

A slow-growing cancer of lymph cells (follicular lymphoma, grade II) affecting lymph nodes in the chest area.

Buddy Insight

Follicular lymphoma grade II involving intrathoracic lymph nodes indicates mediastinal or hilar nodal disease with intermediate-grade histology.

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

C82Follicular lymphoma

C82.1Follicular lymphoma grade II

C82.12Follicular lymphoma grade II, intrathoracic lymph nodes

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C82.12 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C82.12 in this effective period.

Related Child Codes

Official

C82.10Follicular lymphoma grade II, unspecified site

C82.11Follicular lymphoma grade II, lymph nodes of head, face, and neck

C82.13Follicular lymphoma grade II, intra-abdominal lymph nodes

C82.14Follicular lymphoma grade II, lymph nodes of axilla and upper limb

C82.15Follicular lymphoma grade II, lymph nodes of inguinal region and lower limb

Includes

Official

ICD-10-CM does not list Includes notes for C82.12 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C82.12 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C82.12 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for C82.12 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for C82.12 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathology confirming grade II follicular lymphoma

CT or PET/CT documenting intrathoracic lymph node involvement with measurements

Assessment for bulky mediastinal disease (>6-10 cm or >1/3 chest diameter)

Evaluation for compressive symptoms

MEAT Support

HCC Buddy guidance

Pathology confirming grade II follicular lymphoma

CT or PET/CT documenting intrathoracic lymph node involvement with measurements

Assessment for bulky mediastinal disease (>6-10 cm or >1/3 chest diameter)

Evaluation for compressive symptoms

Audit Caution

HCC Buddy guidance

Confusing mediastinal nodal disease with primary mediastinal large B-cell lymphoma (C85.2x) — a distinct entity

Coding pulmonary parenchymal infiltration as intrathoracic nodal disease

Not updating code if disease transforms to aggressive histology on repeat biopsy

Using unspecified site when chest CT clearly shows mediastinal or hilar lymphadenopathy

Common Mistakes

HCC Buddy guidance

C82.02 — Grade I, intrathoracic; differentiate by centroblast count on pathology

C82.22 — Grade III, intrathoracic; higher grade requires different treatment considerations

C85.12 — Unspecified non-Hodgkin lymphoma, intrathoracic; use when subtype not yet confirmed

C82.19 — Grade II, extranodal; lung parenchymal involvement is extranodal, not intrathoracic nodal

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 C82.12 an HCC code?

Yes. C82.12 (Follicular lymphoma grade II, 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: C82.12 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: C82.12
Description: Follicular lymphoma grade II, 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 C82.12 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for C82.12

For C82.12 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 C82.12 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C82.12 is the ICD-10-CM diagnosis code for follicular lymphoma grade ii, intrathoracic lymph nodes. A slow-growing cancer of lymph cells (follicular lymphoma, grade II) affecting lymph nodes in the chest area. C82.12 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, C82.12 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 C82.12; use the applicable model and payment year when reviewing the V28 mapping. 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. 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.

Intrathoracic lymph nodes include mediastinal and hilar nodes; document specific location if available. Because C82.12 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. 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 C82.12 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Intrathoracic lymph nodes include mediastinal and hilar nodes; document specific location if available
•Grade II indicates intermediate differentiation with potential for transformation to higher grades

Clinical Significance

Follicular lymphoma grade II involving intrathoracic lymph nodes indicates mediastinal or hilar nodal disease with intermediate-grade histology. Intrathoracic bulk disease may cause superior vena cava syndrome or airway compression. Grade II designation guides treatment intensity decisions between watch-and-wait and active therapy.

Documentation Requirements

✓Pathology confirming grade II follicular lymphoma
✓CT or PET/CT documenting intrathoracic lymph node involvement with measurements
✓Assessment for bulky mediastinal disease (>6-10 cm or >1/3 chest diameter)
✓Evaluation for compressive symptoms
✓Staging and treatment plan documentation

Commonly Confused Codes

•C82.02: Grade I, intrathoracic; differentiate by centroblast count on pathology
•C82.22: Grade III, intrathoracic; higher grade requires different treatment considerations
•C85.12: Unspecified non-Hodgkin lymphoma, intrathoracic; use when subtype not yet confirmed
•C82.19: Grade II, extranodal; lung parenchymal involvement is extranodal, not intrathoracic nodal