What is ICD-10 code C02.1?

C02.1 is the ICD-10-CM diagnosis code for Malignant neoplasm of border of tongue. Cancer that develops along the edges or sides of the tongue. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C02.1 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C02.1 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. C02.1 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. C02.1 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.

What is the V28 vs V24 difference for C02.1?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For C02.1, V28 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors at RAF 0.545 while V24 mapped to Colorectal, Bladder, and Other Cancers at RAF 0.306. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting C02.1?

Border of tongue includes the lateral margins; verify documentation specifies edge location Do not confuse with anterior two-thirds unspecified (C02.3) which may include border areas Because C02.1 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

C02.1 ICD-10 Code: Malignant neoplasm of border

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 lookupC02.1Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

C02.1

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

Malignant neoplasm of border of tongue

Cancer that develops along the edges or sides of the tongue.

Buddy Insight

Malignant neoplasm of the border (lateral margin) of the tongue is the most common location for oral tongue cancer, accounting for approximately 45% of all tongue malignancies.

CMS-HCC V28

Mapped

HCC 21

Breast, Prostate, Colorectal ...

RAF 0.545

CMS-HCC V24

Mapped

HCC 11

Colorectal, Bladder, and Othe...

RAF 0.306

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 11

Colorectal, Bladder, and Othe...

RAF 0.0

RXHCC

Mapped

HCC 22

Cancer, Other Specified Sites

RAF 0.0

Code Trumping

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Compare selected patient codes to show trumped or trumps impact.

Code Book Path

Official

C02Malignant neoplasm of other and unspecified parts of tongue

C02.1Malignant neoplasm of border of tongue

Inclusion Terms

Official

Malignant neoplasm of tip of tongue

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for C02.1 in this effective period.

Related Child Codes

Official

C02.0Malignant neoplasm of dorsal surface of tongue

C02.2Malignant neoplasm of ventral surface of tongue

C02.3Malignant neoplasm of anterior two-thirds of tongue, part unspecified

C02.4Malignant neoplasm of lingual tonsil

C02.8Malignant neoplasm of overlapping sites of tongue

Includes

Official

ICD-10-CM does not list Includes notes for C02.1 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C02.1 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C02.1 in this effective period.

Use Additional

Official

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

Code Also

Official

ICD-10-CM does not list Code Also instructions for C02.1 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathology confirming malignancy with histologic type (usually squamous cell carcinoma)

Documentation specifying border/lateral margin as the primary site

Laterality documented: right, left, or bilateral involvement

Depth of invasion measured in millimeters (critical for T-staging in 8th edition AJCC)

MEAT Support

HCC Buddy guidance

Pathology confirming malignancy with histologic type (usually squamous cell carcinoma)

Documentation specifying border/lateral margin as the primary site

Laterality documented: right, left, or bilateral involvement

Depth of invasion measured in millimeters (critical for T-staging in 8th edition AJCC)

Audit Caution

HCC Buddy guidance

Using C02.3 (unspecified anterior tongue) when 'lateral tongue' or 'border' is documented — always select the most specific code

Not noting laterality when examining documentation, even though C02.1 itself does not have laterality-specific codes

Confusing a lesion at the junction of lateral tongue and tongue base — if it crosses the circumvallate papillae, it is base of tongue (C01)

Coding resolved/treated cancer as active malignancy

Common Mistakes

HCC Buddy guidance

C02.0 (Malignant neoplasm of dorsal surface) - top surface, not the lateral edge

C02.2 (Malignant neoplasm of ventral surface) - bottom surface, not the lateral edge

C02.3 (Anterior two-thirds, unspecified) - use only when border vs dorsal vs ventral is not documented

C01 (Malignant neoplasm of base of tongue) - posterior location with different staging system

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is C02.1 an HCC code?

Yes. C02.1 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors under the CMS-HCC V28 risk adjustment model (and Colorectal, Bladder, and Other Cancers under V24).

HCC Category Mapping

V28HCC 21, Breast, Prostate, Colorectal and Other Cancers and Tumors

0.545

V24HCC 11, Colorectal, Bladder, and Other Cancers

0.306

ESRDHCC 11, Colorectal, Bladder, and Other Cancers

0.000

RxHCCHCC 22, Cancer, Other Specified Sites

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.

MEAT Criteria for C02.1

For C02.1to 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 C02.1 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

C02.1 is the ICD-10-CM diagnosis code for malignant neoplasm of border of tongue. Cancer that develops along the edges or sides of the tongue. C02.1 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, C02.1 maps to Breast, Prostate, Colorectal and Other Cancers and Tumors (HCC 21) with a community, non-dual, aged base RAF weight of 0.545. Under the older CMS-HCC V24 model, C02.1 maps to Colorectal, Bladder, and Other Cancers (HCC 11) with a community, non-dual, aged base RAF weight of 0.306. 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.

Border of tongue includes the lateral margins; verify documentation specifies edge location. Because C02.1 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 C02.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Border of tongue includes the lateral margins; verify documentation specifies edge location
•Do not confuse with anterior two-thirds unspecified (C02.3) which may include border areas

Clinical Significance

Malignant neoplasm of the border (lateral margin) of the tongue is the most common location for oral tongue cancer, accounting for approximately 45% of all tongue malignancies. The lateral border has the highest concentration of carcinogen exposure from tobacco and alcohol. Early detection is critical as lateral tongue cancers are accessible for clinical examination but can rapidly invade deep musculature.

Documentation Requirements

✓Pathology confirming malignancy with histologic type (usually squamous cell carcinoma)
✓Documentation specifying border/lateral margin as the primary site
✓Laterality documented: right, left, or bilateral involvement
✓Depth of invasion measured in millimeters (critical for T-staging in 8th edition AJCC)
✓Neck lymph node status: clinical and/or pathologic
✓Active treatment plan vs surveillance

Commonly Confused Codes

•C02.0 (Malignant neoplasm of dorsal surface) - top surface, not the lateral edge
•C02.2 (Malignant neoplasm of ventral surface) - bottom surface, not the lateral edge
•C02.3 (Anterior two-thirds, unspecified) - use only when border vs dorsal vs ventral is not documented
•C01 (Malignant neoplasm of base of tongue) - posterior location with different staging system