C79.83 (Secondary malignant neoplasm of oral cavity) compared with D00.00 (Carcinoma in situ of oral cavity, unspecified site), from the official CMS tabular data. C79.83 and D00.00 name the same anatomical site (oral) with a different neoplasm behavior.
Same anatomical site, different neoplasm behavior.
Same site — carcinoma in situ (oral)
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. C79.83 and D00.00 name the same anatomical site (oral) with a different neoplasm behavior.
From the CMS 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.
| C79.83Secondary malignant neoplasm of oral cavity | D00.00Carcinoma in situ of oral cavity, unspecified site | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | C00-D49 — Neoplasms (C00-D49) | C00-D49 — Neoplasms (C00-D49) |
| Definition | — | Carcinoma in situ of oral cavity, unspecified site is a billable ICD-10-CM diagnosis code (D00.00). |
| Includes | — | Bowen's disease erythroplasia grade III intraepithelial neoplasia Queyrat's erythroplasia |
| Use additional code | — | 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