ICD-10 Code C34.1 – Malignant neoplasm of upper lobe, bronchus or lung (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C34.1 – Malignant neoplasm of upper lobe, bronchus or lung
What it is
C34.1 identifies a malignant tumor arising in the upper lobe of the lung or bronchus. Use it when the documentation specifies that the primary cancer site is the upper lobe.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include a lung mass or lesion on imaging, cough, hemoptysis, chest pain, or unexplained weight loss.
When to use this code
Use this code when the provider documents primary malignancy of the upper lobe, bronchus, or lung. It may also apply when pathology, imaging, or specialist notes clearly identify that site. If the record only says “lung cancer” without a lobe, check documentation before assigning C34.1.
Do not use for
Do not use C34.1 for metastatic cancer to the lung or for malignant neoplasms in another lobe. If the site is unspecified or unclear, check documentation.
Coding tip
Verify laterality is not needed here; the key element is the upper-lobe primary site.