ICD-10 Code C34.90 – Malignant neoplasm of unspecified part of unspecified bronchus or lung (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C34.90 – Malignant neoplasm of unspecified part of unspecified bronchus or lung
What it is
This code identifies a malignant tumor in the bronchus or lung when the exact site is not documented. Use it when the record confirms lung cancer but does not specify a lobe, bronchus, or side.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings may include cough, hemoptysis, chest pain, dyspnea, weight loss, or imaging showing a suspicious pulmonary mass.
When to use this code
Use C34.90 when the provider documents primary lung or bronchial cancer without laterality or a more precise subsite. It also applies when pathology, imaging, or the final diagnosis confirms malignancy but the report remains nonspecific. If a more exact location is documented, code that instead.
Do not use for
Do not use this code for metastatic disease to the lung, benign lung tumors, or inflammatory pulmonary nodules. Check documentation if the cancer site is stated elsewhere in the record.
Coding tip
Query for the specific bronchus, lobe, or laterality before defaulting to C34.90.