2026 ICD-10-CM Diagnosis Code C11.9Malignant neoplasm of nasopharynx, unspecified
ICD-10-CM Codes›C00–D49›C00-C14›C11
- Billable — Valid for Submission
- Chronic Condition
C11.9 is a billable ICD-10-CM diagnosis code for malignant neoplasm of nasopharynx, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 146 through 148. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Head and neck cancers - nasopharyngeal.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Adenocarcinoma of nasopharynx
- Adenoid squamous cell carcinoma of nasopharynx
- Basaloid squamous cell carcinoma of nasopharynx
- Keratinizing squamous cell carcinoma of nasopharynx
- Malignant neoplasm of nasal cavity and nasopharynx
- Malignant neoplasm of nasopharyngeal wall
- Malignant neoplasm of nasopharynx
- Nasopharyngeal carcinoma
- Neoplasm of nasal cavity and nasopharynx
- Nonkeratinizing carcinoma of the nasopharynx
- Papillary squamous cell carcinoma of nasopharynx
- Primary acantholytic squamous cell carcinoma
- Primary adenocarcinoma of nasopharynx
- Primary adenoid cystic carcinoma of nasopharynx
- Primary adenoid squamous cell carcinoma of nasopharynx
- Primary basaloid squamous cell carcinoma of nasopharynx
- Primary carcinoma of nasopharynx
- Primary keratinizing squamous cell carcinoma of nasopharynx
- Primary lymphoepithelial carcinoma
- Primary lymphoepithelial carcinoma of nasopharynx
- Primary malignant epithelial neoplasm of nasopharynx
- Primary malignant neoplasm of nasopharynx
- Primary mucoepidermoid carcinoma of nasopharynx
- Primary nonkeratinizing carcinoma of the nasopharynx
- Primary papillary adenocarcinoma of nasopharynx
- Primary papillary squamous cell carcinoma of nasopharynx
- Primary salivary gland type neoplasm of nasopharynx
- Primary squamous cell carcinoma of nasopharynx
- Primary undifferentiated carcinoma of nasopharynx
- Primary undifferentiated nonkeratinizing carcinoma of nasopharynx
- Squamous cell carcinoma of nasopharynx
- Undifferentiated carcinoma of nasopharynx
- Undifferentiated nonkeratinizing carcinoma of nasopharynx
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Inclusion Terms
- Malignant neoplasm of nasopharyngeal wall NOS
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.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Nasopharyngeal Carcinoma
a carcinoma that originates in the epithelium of the nasopharynx and includes four subtypes: keratinizing squamous cell, non-keratinizing, basaloid squamous cell, and papillary adenocarcinoma. it is most prevalent in southeast asian populations and is associated with epstein-barr virus infections. somatic mutations associated with this cancer have been identified in npcr, bap1, ubap1, erbb2, erbb3, mll2, pik3ca, kras, nras, and arid1a genes.
Table of NeoplasmsClinical
Anatomical sites in the Table of Neoplasms that reference this code family.
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 C11.9 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About C11.9Overview
Is C11.9 (Malignant neoplasm of nasopharynx) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of nasopharynx, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does C11.9 group to?
When malignant neoplasm of nasopharynx, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 146, 147, 148, with relative weights from 0.7971 to 2.1174 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of C11.9?
Under the General Equivalence Mappings, malignant neoplasm of nasopharynx, unspecified converts to ICD-9-CM 147.9 (mal neo nasopharynx NOS). The mapping is a direct match.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
