ICD-10 Code C34.9 – Malignant neoplasm of unspecified part of bronchus or lung (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C34.9 – Malignant neoplasm of unspecified part of bronchus or lung
What it is
C34.9 identifies a malignant tumor in the bronchus or lung when the exact location is not documented. Use it when the record confirms lung or bronchial cancer but does not specify a lobe, segment, or side.
Clinical signs
Clinical features vary; refer to documentation. Common findings may include persistent cough, hemoptysis, chest pain, dyspnea, or an abnormal imaging result, but the code is based on the documented diagnosis, not symptoms alone.
When to use this code
Use C34.9 when the provider documents primary malignant neoplasm of the lung or bronchus without further anatomic detail. It also fits cases where pathology or imaging confirms malignancy, but the chart does not identify a specific site. If laterality or lobe is stated, code that level instead.
Do not use for
Do not use this code for metastatic disease to the lung, benign lung tumors, or suspected cancer without confirmation. Check documentation if the record names a specific bronchus, lobe, or overlapping site.
Coding tip
Query for the exact site whenever the note says “lung cancer” or “bronchial cancer” without location detail.