Malignant neoplasm of floor of mouth (C04) ICD-10-CM
The C04 code range covers malignant neoplasm of floor of mouth with 5 ICD-10-CM diagnosis codes. 4 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Use Additional Code
The “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.
Codes in the C04 Range 5 codes · 4 billable
About the C04 Code Range
The ICD-10 code C04 covers malignant neoplasms specifically located on the floor of the mouth, including detailed subcodes for anterior and lateral sites as well as overlapping or unspecified areas. These codes are used to document primary cancers originating in this region.
More specifically, the ICD-10 code for malignant neoplasm of the floor of mouth identifies cancers such as squamous cell carcinoma and melanoma that arise in different parts of the mouth's floor. For instance, C04.0 describes malignancies in the anterior floor, while C04.1 is used for lateral floor tumors. Both codes include synonyms like "primary carcinoma of anterior part of floor of mouth" and "primary carcinoma of lateral part of floor of mouth," aiding coders who encounter alternate terms. Code C04.8 addresses overlapping tumor sites, and C04.9 applies when the specific location within the floor of the mouth is not specified, encompassing terms like "squamous cell carcinoma of floor of mouth" and "malignant melanoma of oral cavity." These codes help healthcare providers accurately classify and report head and neck cancers involving the mouth floor.
Questions About This Page
How many billable codes are in the C04 range?
Of the 5 codes in this range, 4 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the C04 range classify?
The range classifies malignant neoplasm of floor of mouth. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
