C79.31 (Secondary malignant neoplasm of brain) compared with D33.2 (Benign neoplasm of brain, unspecified), from the official CMS tabular data. C79.31 and D33.2 name the same anatomical site (brain) with a different neoplasm behavior. MedCoder-derived
Same anatomical site, different neoplasm behavior.
Same site — benign neoplasm (brain)
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. C79.31 and D33.2 name the same anatomical site (brain) 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.
| C79.31Secondary malignant neoplasm of brain | D33.2Benign neoplasm of brain, unspecified | |
|---|---|---|
| Billing status | Billable | Billable |
| Classification | C00-D49 — Neoplasms | C00-D49 — Neoplasms |
| Definition | Secondary malignant neoplasm of brain is a billable ICD-10-CM diagnosis code (C79.31). | Benign neoplasm of brain, unspecified is a billable ICD-10-CM diagnosis code (D33.2). |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources