C10.9 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

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 lookupC10.9

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)

C10.9

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

Malignant neoplasm of oropharynx, unspecified

Cancer of the oropharynx where the specific location within the middle throat is not documented or specified in the medical record.

Buddy Insight

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

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

C10Malignant neoplasm of oropharynx C10.9Malignant neoplasm of oropharynx, unspecified

Inclusion Terms

Official

No inclusion terms are included in this display for C10.9. Check the code and parent instructions in the Code Book.

Excludes 2

Official

malignant neoplasm of tonsil (C09.-)Inherited from C10

Related Codes

Official

C10.0Malignant neoplasm of vallecula 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

Includes

Official

No Includes notes are included in this display for C10.9. Check the code and parent instructions in the Code Book.

Excludes 1

Official

No Excludes 1 notes are included in this display for C10.9. Check the code and parent instructions in the Code Book.

Code First

Official

No Code First sequencing instructions are included in this display for C10.9. Check the code and parent instructions in the Code Book.

Use Additional

Official

code to identify:Inherited from C10
alcohol abuse and dependence (F10.-)Inherited from C10
exposure to environmental tobacco smoke (Z77.22)Inherited from C10
exposure to tobacco smoke in the perinatal period (P96.81)Inherited from C10
history of tobacco dependence (Z87.891)Inherited from C10
occupational exposure to environmental tobacco smoke (Z57.31)Inherited from C10
tobacco dependence (F17.-)Inherited from C10
tobacco use (Z72.0)Inherited from C10

Code Also

Official

No Code Also instructions are included in this display for C10.9. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Pathology confirmation of oropharyngeal malignancy

Documentation of provider query for specific subsite

HPV/p16 status (critical for all oropharyngeal cancers)

Review of all imaging and endoscopy reports for subsite identification

MEAT Support

HCC Buddy guidance

Pathology confirmation of oropharyngeal malignancy

Documentation of provider query for specific subsite

HPV/p16 status (critical for all oropharyngeal cancers)

Review of all imaging and endoscopy reports for subsite identification

Audit Caution

HCC Buddy guidance

Defaulting to this code without reviewing endoscopy, imaging, and pathology reports that typically specify the subsite

Not querying the provider, especially the head and neck surgeon or radiation oncologist who will know the exact location

Using this code when documentation says 'throat cancer' without confirming it is specifically oropharyngeal

Missing the opportunity to query for HPV status which is critical for oropharyngeal cancer management

Common Mistakes

HCC Buddy guidance

C10.0 — Vallecula; check endoscopy reports for specific subsite

C09.9 — Tonsil, unspecified; more specific if at least tonsillar origin is known

C14.0 — Pharynx, unspecified; even less specific — use C10.9 when at least oropharynx is identified

C10.2 — Lateral wall of oropharynx; frequently identifiable on imaging

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 C10.9 an HCC code?

Yes. C10.9 (Malignant neoplasm of oropharynx, unspecified) 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: C10.9 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: C10.9
Description: Malignant neoplasm of oropharynx, unspecified
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

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 C10.9 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C10.9

For C10.9, 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

C10.9 is the ICD-10-CM diagnosis code for malignant neoplasm of oropharynx, unspecified. Cancer of the oropharynx where the specific location within the middle throat is not documented or specified in the medical record. C10.9 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, C10.9 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.

This is a default code used when oropharyngeal cancer is diagnosed but the exact anatomical site is not specified. For C10.9, 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 C10.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is a default code used when oropharyngeal cancer is diagnosed but the exact anatomical site is not specified
•Query the provider to obtain more specific site information (C10.0-C10.4) for more accurate coding when possible

Clinical Significance

Malignant neoplasm of oropharynx, unspecified, is the least specific oropharyngeal cancer code and should be used only when the precise subsite truly cannot be determined from available documentation. Given the prognostic and treatment importance of exact oropharyngeal site identification, this code signals a documentation improvement opportunity.

Documentation Requirements

✓Pathology confirmation of oropharyngeal malignancy
✓Documentation of provider query for specific subsite
✓HPV/p16 status (critical for all oropharyngeal cancers)
✓Review of all imaging and endoscopy reports for subsite identification
✓Explanation for why specific subsite cannot be determined

Commonly Confused Codes

•C10.0: Vallecula; check endoscopy reports for specific subsite
•C09.9: Tonsil, unspecified; more specific if at least tonsillar origin is known
•C14.0: Pharynx, unspecified; even less specific: use C10.9 when at least oropharynx is identified
•C10.2: Lateral wall of oropharynx; frequently identifiable on imaging