C02.4 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 · free HCC coding tools

ICD-10-CM Code View

HCC Buddy Code Card

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

Code lookupC02.4

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lip, oral cavity and pharynx (C00-C14)

C02.4

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

Malignant neoplasm of lingual tonsil

Cancer of the lingual tonsil, which is lymphoid tissue located at the base of the tongue.

Buddy Insight

Malignant neoplasm of the lingual tonsil is a cancer of the lymphoid tissue at the base of the tongue.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 21

Lymphoma and Other Cancers

Coefficient HCC 21: 0.671 (Community Non-Dual Aged (CNA))

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 011

HHS-HCC 011 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 11

Colorectal/Bladder/and Other ...

Code-level coefficient reference

RXHCC

Mapped

HCC 22

Prostate, Breast, Bladder, an...

Code-level coefficient reference

Code Book Path

Official

C02Malignant neoplasm of other and unspecified parts of tongue C02.4Malignant neoplasm of lingual tonsil

Inclusion Terms

Official

No inclusion terms are included in this display for C02.4. Check the code and parent instructions in the Code Book.

Excludes 2

Official

malignant neoplasm of tonsil NOS (C09.9)

Related Codes

Official

C02.0Malignant neoplasm of dorsal surface of tongue C02.1Malignant neoplasm of border of tongue C02.2Malignant neoplasm of ventral surface of tongue C02.3Malignant neoplasm of anterior two-thirds of tongue, part unspecified C02.8Malignant neoplasm of overlapping sites of tongue

Includes

Official

No Includes notes are included in this display for C02.4. Check the code and parent instructions in the Code Book.

Excludes 1

Official

No Excludes 1 notes are included in this display for C02.4. Check the code and parent instructions in the Code Book.

Code First

Official

No Code First sequencing instructions are included in this display for C02.4. Check the code and parent instructions in the Code Book.

Use Additional

Official

code to identify:Inherited from C02
alcohol abuse and dependence (F10.-)Inherited from C02
history of tobacco dependence (Z87.891)Inherited from C02
tobacco dependence (F17.-)Inherited from C02
tobacco use (Z72.0)Inherited from C02

Code Also

Official

No Code Also instructions are included in this display for C02.4. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Pathology confirming malignancy with histologic type (squamous cell carcinoma vs lymphoma)

HPV/p16 immunohistochemistry status documented

Documentation specifying lingual tonsil as distinct from palatine tonsil

TNM staging (staged as oropharyngeal cancer)

MEAT Support

HCC Buddy guidance

Pathology confirming malignancy with histologic type (squamous cell carcinoma vs lymphoma)

HPV/p16 immunohistochemistry status documented

Documentation specifying lingual tonsil as distinct from palatine tonsil

TNM staging (staged as oropharyngeal cancer)

Audit Caution

HCC Buddy guidance

Confusing lingual tonsil (at tongue base) with palatine tonsil (in the oropharyngeal wall) — different anatomic sites with different codes

Not confirming histology — lymphomas of the lingual tonsil should be coded to the lymphoma category (C81-C85), not C02.4

Missing HPV status documentation which impacts staging and prognosis reporting

Using C01 (base of tongue) when lingual tonsil is specifically documented — the more specific code is preferred

Common Mistakes

HCC Buddy guidance

C01 (Malignant neoplasm of base of tongue) - base of tongue is the broader anatomic region; lingual tonsil is specific lymphoid tissue within it

C09.9 (Malignant neoplasm of tonsil, unspecified) - palatine tonsil, not lingual tonsil

C09.0 (Malignant neoplasm of tonsillar fossa) - tonsillar fossa is the palatine tonsil area, not lingual

C83.30 (Diffuse large B-cell lymphoma, unspecified site) - if the tumor is lymphoma rather than carcinoma, lymphoma codes may be more appropriate

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 C02.4 an HCC code?

Yes. C02.4 (Malignant neoplasm of lingual tonsil) 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: C02.4 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: C02.4
Description: Malignant neoplasm of lingual tonsil
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 11, Colorectal/Bladder/and Other Cancers

Not separately weighted

RxHCCHCC 22, Prostate, Breast, Bladder, and Other Cancers and Tumors

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 C02.4 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C02.4

For C02.4, 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

C02.4 is the ICD-10-CM diagnosis code for malignant neoplasm of lingual tonsil. Cancer of the lingual tonsil, which is lymphoid tissue located at the base of the tongue. C02.4 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lip, oral cavity and pharynx (c00-c14).

Under the CMS-HCC V28 risk adjustment model, C02.4 maps to Lymphoma and Other Cancers (HCC 21) with a source-labeled community, non-dual, aged reference coefficient of 0.671. 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.

Lingual tonsil is distinct from palatine tonsils; verify the specific lymphoid tissue involved. For C02.4, 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 C02.4 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Lingual tonsil is distinct from palatine tonsils; verify the specific lymphoid tissue involved
•Confirm histology as these may be lymphomas rather than squamous cell carcinomas

Clinical Significance

Malignant neoplasm of the lingual tonsil is a cancer of the lymphoid tissue at the base of the tongue. These tumors may be squamous cell carcinoma or lymphoma, and the distinction is critical for treatment planning. HPV-associated squamous cell carcinomas of the lingual tonsil have dramatically better prognosis than HPV-negative tumors, making HPV/p16 testing essential.

Documentation Requirements

✓Pathology confirming malignancy with histologic type (squamous cell carcinoma vs lymphoma)
✓HPV/p16 immunohistochemistry status documented
✓Documentation specifying lingual tonsil as distinct from palatine tonsil
✓TNM staging (staged as oropharyngeal cancer)
✓Neck lymph node status documented
✓Active vs historical cancer status

Excludes 2, Not included here, may code separately

malignant neoplasm of tonsil NOS (C09.9)

Commonly Confused Codes

•C01 (Malignant neoplasm of base of tongue) - base of tongue is the broader anatomic region; lingual tonsil is specific lymphoid tissue within it
•C09.9 (Malignant neoplasm of tonsil, unspecified) - palatine tonsil, not lingual tonsil
•C09.0 (Malignant neoplasm of tonsillar fossa) - tonsillar fossa is the palatine tonsil area, not lingual
•C83.30 (Diffuse large B-cell lymphoma, unspecified site) - if the tumor is lymphoma rather than carcinoma, lymphoma codes may be more appropriate