Malignant neoplasm of floor of mouth, unspecified

This code signifies a cancerous tumor originating in the floor of the mouth, the U-shaped area beneath the tongue. It indicates that the specific subsite or extent of the malignancy within the floor of the mouth has not been documented. This is a primary malignant neoplasm, not a secondary or metastatic site.

Use this code when documentation confirms a malignant neoplasm of the floor of the mouth, but the provider has not specified a more precise anatomical location (e.g., anterior, lateral). This code is appropriate when the medical record lacks the detail to assign a more specific C04.x code.

• Avoid using this code if the documentation specifies a more precise location within the floor of the mouth (e.g., C04.0 for anterior floor of mouth).
• Always review pathology reports and operative notes for greater specificity regarding tumor location and histology.
• Sequence this code as the primary diagnosis when it is the reason for the encounter or treatment.