Malignant neoplasm of overlapping sites of nasopharynx

This code signifies a cancerous tumor that spans across two or more adjacent anatomical subsites within the nasopharynx, where the point of origin cannot be clearly identified as arising from a single subsite. This includes malignancies affecting areas like the posterior superior wall, lateral wall, and floor of the nasopharynx simultaneously.

Apply this code when documentation explicitly states a malignant neoplasm involving overlapping or contiguous sites of the nasopharynx. This is typically supported by pathology reports, imaging studies, and physician notes describing the extent of the tumor. Use when the tumor's origin cannot be localized to a single, specific nasopharyngeal subsite.

• Do not use if the tumor clearly originates from a single, identifiable subsite of the nasopharynx (e.g., C11.0 for superior wall).
• Ensure the medical record explicitly states "overlapping" or "contiguous" involvement of multiple nasopharyngeal sites.
• Always sequence this code as the primary diagnosis when it represents the main reason for the encounter.