C34.0 (Malignant neoplasm of main bronchus) compared with C78.39 (Secondary malignant neoplasm of other respiratory organs), from the official CMS tabular data. C34.0 and C78.39 name the same anatomical site (cartilage) with a different neoplasm behavior. MedCoder-derived
Same anatomical site, different neoplasm behavior.
Same site — secondary malignancy (cartilage)
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. C34.0 and C78.39 name the same anatomical site (cartilage) 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.
| C34.0Malignant neoplasm of main bronchus | C78.39Secondary malignant neoplasm of other respiratory organs | |
|---|---|---|
| Billing status | Non-billable header | Billable |
| Classification | C00-D49 — Neoplasms (C00-D49) | C00-D49 — Neoplasms (C00-D49) |
| Definition | Malignant neoplasm of main bronchus is a non-billable ICD-10-CM category code (C34.0). | Secondary malignant neoplasm of other respiratory organs is a billable ICD-10-CM diagnosis code (C78.39). |
| Includes | malignant neoplasm of middle ear Malignant neoplasm of carina Malignant neoplasm of hilus (of lung) | — |
| 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