C04.0 (Malignant neoplasm of anterior floor of mouth) compared with D00.06 (Carcinoma in situ of floor of mouth), from the official CMS tabular data. C04.0 and D00.06 name the same anatomical site (mouth) with a different neoplasm behavior. MedCoder-derived
Same anatomical site, different neoplasm behavior.
Same site — carcinoma in situ (mouth)
The behavior documented for the site — malignant primary, secondary, carcinoma in situ, benign, uncertain or unspecified — decides which column of the neoplasm table, and therefore which code, applies.
Source: CMS Table of Neoplasms
Same site, different neoplasm behavior. C04.0 and D00.06 name the same anatomical site (mouth) with a different neoplasm behavior.
From the CMS/CDC Table of Neoplasms: the behavior documented for that site — malignant primary, secondary, carcinoma in situ, benign, uncertain or unspecified — decides which column, and therefore which code, applies.
| C04.0Malignant neoplasm of anterior floor of mouth | D00.06Carcinoma in situ of floor of mouth | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | C00-D49 — Neoplasms | C00-D49 — Neoplasms |
| Definition | Malignant neoplasm of anterior floor of mouth is a billable ICD-10-CM diagnosis code (C04.0). | Carcinoma in situ of floor of mouth is a billable ICD-10-CM diagnosis code (D00.06). |
| Includes | Malignant neoplasm of anterior to the premolar-canine junction | Bowen's disease erythroplasia grade III intraepithelial neoplasia Queyrat's erythroplasia |
| Use additional code | code to identify: alcohol abuse and dependence (F10.-) history of tobacco dependence (Z87.891) | code to identify: exposure to environmental tobacco smoke (Z77.22) exposure to tobacco smoke in the perinatal period (P96.81) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources