ICD-10 Code C11 – Malignant neoplasm of nasopharynx (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C11 – Malignant neoplasm of nasopharynx
What it is
C11 identifies a malignant tumor arising in the nasopharynx, the upper part of the throat behind the nose. Use it when documentation states nasopharyngeal cancer or malignant neoplasm of the nasopharynx.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include nasal obstruction, epistaxis, ear symptoms from Eustachian tube involvement, neck mass, or other signs of a nasopharyngeal mass.
When to use this code
Use C11 when the provider documents a primary malignant neoplasm in the nasopharynx. It also applies when the record clearly identifies nasopharyngeal carcinoma without a more specific subsite code. Check documentation if laterality, histology, or staging details are present.
Do not use for
Do not use C11 for benign nasopharyngeal lesions, inflammatory disease, or malignant tumors arising in another head and neck site. If the record does not confirm malignancy, check documentation.
Coding tip
Code the documented primary site first, and verify whether a more specific nasopharynx subcategory is available before assigning C11.