2026 ICD-10-CM Diagnosis Code C13.1Malignant neoplasm of aryepiglottic fold, hypopharyngeal aspect
ICD-10-CM Codes›C00–D49›C00-C14›C13
- Billable — Valid for Submission
- Risk Adjusts — HCC 21
- Chronic Condition
C13.1 is a billable ICD-10-CM diagnosis code for malignant neoplasm of aryepiglottic fold, hypopharyngeal aspect. 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 - hypopharyngeal.
For Medicare Advantage risk adjustment, C13.1 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
Code Classification
Medicare Risk Adjustment (HCC)Billing
C13.1 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.
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.
- Malignant neoplasm of junctional region of epiglottis
- Malignant tumor aryepiglottic fold - hypopharyngeal aspect
- Neoplasm of hypopharyngeal aspect of aryepiglottic fold
- Neoplasm of hypopharyngeal aspect of interarytenoid fold
- Primary malignant neoplasm of epiglottis
- Primary malignant neoplasm of hypopharyngeal aspect of aryepiglottic fold
- Primary malignant neoplasm of hypopharyngeal aspect of interarytenoid fold
- Primary malignant neoplasm of soft tissues of neck
- Primary squamous cell carcinoma of aryepiglottic fold
- Primary squamous cell carcinoma of hypopharyngeal aspect of aryepiglottic fold
- Primary squamous cell carcinoma of hypopharynx
- Primary squamous cell carcinoma of supraglottis
- Squamous cell carcinoma of epiglottis
- Squamous cell carcinoma of head and neck
- Squamous cell carcinoma of hypopharyngeal aspect of aryepiglottic fold
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Malignant neoplasm of aryepiglottic fold, marginal zone
- Malignant neoplasm of aryepiglottic fold NOS
- Malignant neoplasm of interarytenoid fold, marginal zone
- Malignant neoplasm of interarytenoid fold NOS
Type 2 Excludes
- malignant neoplasm of aryepiglottic fold or interarytenoid fold, laryngeal aspect C32.1
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Squamous Cell Carcinoma of Head and Neck
the most common type of head and neck carcinoma that originates from cells on the surface of the nasal cavity; mouth; paranasal sinuses, salivary glands, and larynx. mutations in tnfrsf10b, pten, and ing1 genes are associated with this cancer.
Table of NeoplasmsClinical
Anatomical sites in the Table of Neoplasms that reference this code family.
| Site | Malig. Primary | Malig. Secondary | Ca in situ | Benign | Uncertain | Unspec. |
|---|---|---|---|---|---|---|
| aryepiglottic fold | C13.1 | C79.89 | D00.08 | D10.7 | D37.05 | D49.0 |
| aryepiglottic fold › hypopharyngeal aspect | C13.1 | C79.89 | D00.08 | D10.7 | D37.05 | D49.0 |
| aryepiglottic fold › marginal zone | C13.1 | C79.89 | D00.08 | D10.7 | D37.05 | D49.0 |
| interarytenoid fold | C13.1 | C79.89 | D00.08 | D10.7 | D37.05 | D49.0 |
| interarytenoid fold › hypopharyngeal aspect | C13.1 | C79.89 | D00.08 | D10.7 | D37.05 | D49.0 |
| interarytenoid fold › marginal zone | C13.1 | C79.89 | D00.08 | D10.7 | 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 C13.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C13.1Overview
What is the ICD-10 code for malignant neoplasm of aryepiglottic fold, hypopharyngeal aspect?
The ICD-10-CM code for malignant neoplasm of aryepiglottic fold, hypopharyngeal aspect is C13.1 (sometimes written as C131). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is C13.1 (Malignant neoplasm of hypopharynx) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of aryepiglottic fold, hypopharyngeal aspect on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C13.1 group to?
When malignant neoplasm of aryepiglottic fold, hypopharyngeal aspect 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 C13.1?
Under the General Equivalence Mappings, malignant neoplasm of aryepiglottic fold, hypopharyngeal aspect converts to ICD-9-CM 148.2 (mal neo aryepiglott fold). The mapping is a direct match.
What HCC is C13.1?
C13.1 (malignant neoplasm of aryepiglottic fold, hypopharyngeal aspect) 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 C13.1 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, C13.1 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.
