ICD-10 Code C34.00 – Malignant neoplasm of unspecified main bronchus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C34.00 – Malignant neoplasm of unspecified main bronchus
What it is
This code identifies a malignant tumor in the main bronchus when the side is not specified. Use it for documented cancer involving the primary airway branch, not a benign or metastatic lesion.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include persistent cough, hemoptysis, wheeze, dyspnea, or imaging/bronchoscopy evidence of a bronchial mass.
When to use this code
Use C34.00 when the provider documents primary cancer of the main bronchus without stating right or left. It also fits pathology or imaging reports that confirm malignancy but do not specify laterality. If the record identifies a side, choose the more specific bronchus code instead.
Do not use for
Do not use this code for lung cancers limited to other bronchial sites, metastatic disease to the bronchus, or benign bronchial tumors. Check documentation if the primary site or laterality is unclear.
Coding tip
Look for laterality in the final pathology, operative note, or imaging report before defaulting to the unspecified code.