What is ICD-10 code C10.0?

C10.0 is the ICD-10-CM diagnosis code for Malignant neoplasm of vallecula. Cancer located in the vallecula, which is a small depression or pocket at the base of the tongue in the throat. It belongs to the ICD-10-CM chapter for neoplasms (c00-d49). C10.0 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. C10.0 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. C10.0 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. C10.0 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 C10.0?

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 C10.0, V28 maps to Lymphoma and Other Cancers at RAF 0.671 while V24 mapped to Colorectal, Bladder, and Other Cancers at RAF 0.307. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting C10.0?

The vallecula is a specific anatomical site in the oropharynx located between the base of the tongue and the epiglottis Ensure documentation specifically mentions the vallecula to distinguish from other oropharyngeal sites Because C10.0 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.

2026 ICD-10-CM C10.0: Malignant neoplasm

ICD-10-CM Code View

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Code lookupC10.0Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

C10.0

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

Malignant neoplasm of vallecula

Cancer located in the vallecula, which is a small depression or pocket at the base of the tongue in the throat.

Buddy Insight

Malignant neoplasm of the vallecula is an oropharyngeal cancer arising in the depression between the base of the tongue and the epiglottis.

CMS-HCC V28

Mapped

HCC 21

Lymphoma and Other Cancers

RAF 0.671

CMS-HCC V24

Mapped

HCC 11

Colorectal, Bladder, and Othe...

RAF 0.307

ACA/HHS

Mapped

HCC 11

HHS-HCC 11

Varies by metal level

ESRD/PACE

Mapped

HCC 11

Colorectal, Bladder, and Othe...

RAF 0.059

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

C10Malignant neoplasm of oropharynx

C10.0Malignant neoplasm of vallecula

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for C10.0 in this effective period.

Excludes 2

Official

malignant neoplasm of tonsil (C09.-)

Related Child Codes

Official

C10.1Malignant neoplasm of anterior surface of epiglottis

C10.2Malignant neoplasm of lateral wall of oropharynx

C10.3Malignant neoplasm of posterior wall of oropharynx

C10.4Malignant neoplasm of branchial cleft

C10.8Malignant neoplasm of overlapping sites of oropharynx

Includes

Official

ICD-10-CM does not list Includes notes for C10.0 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for C10.0 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for C10.0 in this effective period.

Use Additional

Official

code to identify:
alcohol abuse and dependence (F10.-)
exposure to environmental tobacco smoke (Z77.22)
exposure to tobacco smoke in the perinatal period (P96.81)
history of tobacco dependence (Z87.891)

Code Also

Official

ICD-10-CM does not list Code Also instructions for C10.0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Pathology-confirmed malignancy with histological type

Specific documentation of vallecula as primary site (not just 'base of tongue')

HPV/p16 status

Assessment of airway compromise and swallowing function

MEAT Support

HCC Buddy guidance

Pathology-confirmed malignancy with histological type

Specific documentation of vallecula as primary site (not just 'base of tongue')

HPV/p16 status

Assessment of airway compromise and swallowing function

Audit Caution

HCC Buddy guidance

Confusing vallecula with base of tongue (C01) — the vallecula is the groove between the tongue base and epiglottis, not the tongue base itself

Using epiglottic codes when the tumor is in the vallecula, which is a distinct oropharyngeal site

Not recognizing that vallecula tumors are classified as oropharyngeal (C10.0) rather than laryngeal even though they border the epiglottis

Missing airway compromise assessment which is critical for tumors in this location

Common Mistakes

HCC Buddy guidance

C01 — Malignant neoplasm of base of tongue; the vallecula is between the tongue base and epiglottis, not the tongue base itself

C10.1 — Anterior surface of epiglottis; the vallecula is adjacent to but distinct from the epiglottis

C10.9 — Oropharynx, unspecified; avoid when vallecula is documented

C32.1 — Supraglottis; vallecula is oropharyngeal, not laryngeal

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 C10.0 an HCC code?

Yes. C10.0 (Malignant neoplasm of vallecula) maps to Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model (and Colorectal, Bladder, and Other Cancers under V24), with a community non-dual aged RAF of 0.671. It is billable for payment year 2026.

Coder answer: C10.0 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: C10.0
Description: Malignant neoplasm of vallecula
HCC (V28): HCC 21 — Lymphoma and Other Cancers
RAF: 0.671
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 21, Lymphoma and Other Cancers

0.671

V24HCC 11, Colorectal, Bladder, and Other Cancers

0.307

ESRDHCC 11, Colorectal, Bladder, and Other Cancers

0.059

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 C10.0 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for C10.0

For C10.0 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 C10.0 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

C10.0 is the ICD-10-CM diagnosis code for malignant neoplasm of vallecula. Cancer located in the vallecula, which is a small depression or pocket at the base of the tongue in the throat. C10.0 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, C10.0 maps to Lymphoma and Other Cancers (HCC 21) with a community, non-dual, aged base RAF weight of 0.671. Under the older CMS-HCC V24 model, C10.0 maps to Colorectal, Bladder, and Other Cancers (HCC 11) with a community, non-dual, aged base RAF weight of 0.307. 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.

The vallecula is a specific anatomical site in the oropharynx located between the base of the tongue and the epiglottis. Because C10.0 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 C10.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•The vallecula is a specific anatomical site in the oropharynx located between the base of the tongue and the epiglottis
•Ensure documentation specifically mentions the vallecula to distinguish from other oropharyngeal sites

Clinical Significance

Malignant neoplasm of the vallecula is an oropharyngeal cancer arising in the depression between the base of the tongue and the epiglottis. This is an important anatomical landmark for head and neck oncology because tumors here may obstruct the airway and significantly impair swallowing function.

Documentation Requirements

✓Pathology-confirmed malignancy with histological type
✓Specific documentation of vallecula as primary site (not just 'base of tongue')
✓HPV/p16 status
✓Assessment of airway compromise and swallowing function
✓TNM staging with imaging to assess depth of invasion and relationship to epiglottis

Commonly Confused Codes

•C01: Malignant neoplasm of base of tongue; the vallecula is between the tongue base and epiglottis, not the tongue base itself
•C10.1: Anterior surface of epiglottis; the vallecula is adjacent to but distinct from the epiglottis
•C10.9: Oropharynx, unspecified; avoid when vallecula is documented
•C32.1: Supraglottis; vallecula is oropharyngeal, not laryngeal