ICD-10 Code C11.8 – Malignant neoplasm of overlapping sites of nasopharynx (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C11.8 – Malignant neoplasm of overlapping sites of nasopharynx
What it is
This code identifies a malignant tumor of the nasopharynx that involves overlapping anatomic sites, so no single subsite can be assigned. Use it when documentation states overlap within the nasopharynx.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include a nasopharyngeal mass, nasal obstruction, epistaxis, ear symptoms, or cervical lymphadenopathy, but you should code only what is documented.
When to use this code
Use C11.8 when the provider documents a malignant neoplasm of the nasopharynx spanning overlapping sites or crossing subsite boundaries. It is appropriate when the record does not support a more specific nasopharyngeal subsite.
If the tumor is described only as nasopharyngeal cancer without a clear site, check the operative note, pathology report, or oncology assessment before assigning the code. Do not infer overlap from incomplete wording.
Do not use for
Do not use this code for benign nasopharyngeal lesions, metastatic disease to the nasopharynx, or a clearly documented single nasopharyngeal subsite. Check documentation.
Coding tip
Code C11.8 only when overlap is explicitly stated or clearly supported by the record; otherwise query for a more specific nasopharyngeal site.