Malignant neoplasm of base of tongue

This code signifies a cancerous tumor originating in the base of the tongue, the posterior one-third of the tongue located behind the circumvallate papillae. This malignancy is a type of oral cavity cancer, often associated with risk factors such as tobacco and alcohol use, and increasingly, human papillomavirus (HPV) infection.

Use this code for documented cases of primary malignant neoplasm specifically affecting the base of the tongue. Supporting documentation should clearly identify the tumor's location as the base of the tongue, confirmed by pathology reports or physician statements. This code is appropriate for initial diagnosis, treatment, and follow-up of this specific cancer.

• Ensure documentation specifies "base of tongue" to differentiate from other tongue subsites.
• Do not use for benign neoplasms or malignancies of other parts of the tongue (e.g., anterior two-thirds).
• Always sequence this code as the primary diagnosis when it is the reason for the encounter, followed by any relevant secondary diagnoses.