2026 ICD-10-CM Diagnosis Code C10.9Malignant neoplasm of oropharynx, unspecified

ICD-10-CM C10.9

CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C10.9 is a billable ICD-10-CM diagnosis code for malignant neoplasm of oropharynx, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 11 through 13, 146 through 148. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Head and neck cancers - throat.

For Medicare Advantage risk adjustment, C10.9 maps to CMS-HCC Category 21 (Lymphoma and Other Cancers) under the V28 model, adding a risk factor of about 0.671 for a community, non-dual, aged beneficiary in payment year 2026.

Code Identity

ICD-10-CM Code

C10.9

Billable Status

Yes — Valid for Submission

Code Describes

Malignant neoplasm of oropharynx, unspecified

Short Description

Malignant neoplasm of oropharynx, unspecified

Same as the full description in the CMS dataset.

Parent Code

C10

Malignant neoplasm of oropharynx

Code Classification

ChapterC00–D49Neoplasms

SectionC00-C14Malignant neoplasms of lip, oral cavity and pharynx

CategoryC10Malignant neoplasm of oropharynx

This CodeC10.9Malignant neoplasm of oropharynx, unspecified

Medicare Risk Adjustment (HCC)Billing

C10.9 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2026.

CMS-HCC V28 Category (Payment Model)

HCC 21— Lymphoma and Other Cancers

Payment HCC · PY 2026 one of 463 ICD-10-CM codes in this category

Risk Adjustment Factor (RAF) Weight

+0.671

community, non-dual, aged · ranges 0.493–0.739 across segments

Hierarchy

Superseded by HCC 17, HCC 18, HCC 19, and HCC 20

a more severe related category takes the payment when both are reported

Prior Model (CMS-HCC V24)

HCC 11

V24 retired V28 pays 100% of MA risk scores since PY 2026

Other CMS Models

PACE (CMS-HCC V22): HCC 11 · ESRD (V21): HCC 11 · ESRD (V24): HCC 11

ESRD V21 weights: 0.076 dialysis, 0.284–0.298 functioning graft · ESRD V24 weights: 0.059 dialysis, 0.257–0.362 functioning graft

Part D (RxHCC)

Not mapped

C10.9 does not risk-adjust in the RxHCC prescription drug model

Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

Filter synonyms:

Acinar cell carcinoma of oropharynx
Adenocarcinoma of oropharynx
Adenoid cystic carcinoma of oropharynx
Adenosquamous carcinoma of oropharynx
Basal cell adenocarcinoma of oropharynx
Basaloid carcinoma of oropharynx
Basaloid squamous cell carcinoma of oropharynx
Carcinoma ex pleomorphic adenoma of oropharynx
Clear cell adenocarcinoma of oropharynx
Cystadenocarcinoma of oropharynx
Epithelial-myoepithelial carcinoma of oropharynx
Infiltrating duct carcinoma of oropharynx
Lymphoepithelial carcinoma of oropharynx
Malignant epithelial neoplasm of oropharynx
Malignant neoplasm of oropharynx
Mucinous adenocarcinoma of oropharynx
Mucoepidermoid carcinoma of oropharynx
Myoepithelial carcinoma
Myoepithelial carcinoma of oropharynx
Oncocytic carcinoma of oropharynx
Oxyphilic adenocarcinoma
Papillary adenocarcinoma of oropharynx
Papillary squamous cell carcinoma of oropharynx
Polymorphous low grade adenocarcinoma of oropharynx
Primary acinar cell carcinoma of oropharynx
Primary adenocarcinoma of oropharynx
Primary adenoid cystic carcinoma of oropharynx
Primary adenosquamous carcinoma of oropharynx
Primary adenosquamous cell carcinoma
Primary basal cell adenocarcinoma of oropharynx
Primary basaloid carcinoma of oropharynx
Primary basaloid squamous cell carcinoma of oropharynx
Primary carcinoma ex pleomorphic adenoma of oropharynx
Primary clear cell adenocarcinoma of oropharynx
Primary cystadenocarcinoma of oropharynx
Primary epithelial-myoepithelial carcinoma of oropharynx
Primary infiltrating duct carcinoma of oropharynx
Primary lymphoepithelial carcinoma
Primary lymphoepithelial carcinoma of oropharynx
Primary malignant neoplasm of oropharynx
Primary mucinous adenocarcinoma of oropharynx
Primary mucinous carcinoma of digestive organ
Primary mucoepidermoid carcinoma of oropharynx
Primary myoepithelial carcinoma of oropharynx
Primary oxyphilic adenocarcinoma
Primary oxyphilic adenocarcinoma of oropharynx
Primary papillary adenocarcinoma of oropharynx
Primary papillary squamous cell carcinoma of oropharynx
Primary polymorphous low grade adenocarcinoma of oropharynx
Primary salivary gland-type tumor of oropharynx
Primary spindle cell squamous cell carcinoma
Primary spindle cell squamous cell carcinoma of oropharynx
Primary squamous cell carcinoma of oropharynx
Primary undifferentiated carcinoma of oropharynx
Salivary gland type carcinoma of oropharynx
Spindle cell squamous cell carcinoma of oropharynx
Squamous cell carcinoma of oropharynx

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NEO003

Head and neck cancers - throat

Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

Oropharyngeal Neoplasms
tumors or cancer of the oropharynx.
Oropharynx
the middle portion of the pharynx that lies posterior to the mouth, inferior to the soft palate, and superior to the base of the tongue and epiglottis. it has a digestive function as food passes from the mouth into the oropharynx before entering esophagus.

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

Filter table of neoplasms:

Site	Malig. Primary	Malig. Secondary	Ca in situ	Benign	Uncertain	Unspec.
fauces, faucial NEC	C10.9	C79.89	D00.08	D10.5	D37.05	D49.0
oropharynx	C10.9	C79.89	D00.08	D10.5	D37.05	D49.0

Patient EducationClinical

Throat Cancer

Throat cancer is a type of head and neck cancer. Throat cancer has different names, depending on which part of the throat is affected. The different parts of your throat are called the oropharynx, the hypopharynx, the nasopharynx, and the larynx, or voice box.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert C10.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM

146.9 Malig neo oropharynx NOS

Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.

FY 2017–2025No changes

FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About C10.9Overview

What is the ICD-10 code for malignant neoplasm of oropharynx, unspecified?

The ICD-10-CM code for malignant neoplasm of oropharynx, unspecified is C10.9 (sometimes written as C109). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Is C10.9 (Malignant neoplasm of oropharynx) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of oropharynx, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does C10.9 group to?

When malignant neoplasm of oropharynx, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 11, 12, 13, 146, 147, 148, with relative weights from 0.7971 to 5.4541 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of C10.9?

Under the General Equivalence Mappings, malignant neoplasm of oropharynx, unspecified converts to ICD-9-CM 146.9 (malig neo oropharynx NOS). The mapping is a direct match.

What HCC is C10.9?

C10.9 (malignant neoplasm of oropharynx, unspecified) maps to CMS-HCC Category 21 (Lymphoma and Other Cancers), commonly written as HCC 21, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2026. It mapped to HCC 11 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. It does not map to any RxHCC in the Part D prescription drug model.

Does C10.9 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, C10.9 adds a risk adjustment factor of about 0.671 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.493 to 0.739 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, and HCC 20) supersedes it when both are reported. See the full factor table on the HCC 21 category page.

Indicator	Meaning	CMS pays CC/MCC DRG
Y	Diagnosis was present at the time of inpatient admission	Yes
N	Diagnosis was not present at the time of admission	No
U	Documentation is insufficient to determine	No
W	Clinically undetermined	Yes
1	Unreported, exempt from POA reporting	No