ICD-10 Code C78.02 – Secondary malignant neoplasm of left lung (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C78.02 – Secondary malignant neoplasm of left lung
What it is
This code identifies metastatic cancer involving the left lung. It means a malignant tumor started elsewhere in the body and spread to the left lung.
Clinical signs
Findings may include pulmonary nodules or masses on imaging, cough, dyspnea, chest discomfort, or hemoptysis. Clinical features vary; refer to documentation.
When to use this code
Use C78.02 when the record clearly states secondary malignant neoplasm of the left lung or left lung metastasis. Apply it when the left lung is the documented metastatic site, even if the primary cancer is coded separately. Check documentation if laterality is unclear.
Do not use for
Do not use this code for primary lung cancer, unspecified lung metastasis, or metastatic disease in another organ. If the note does not specify the left lung, choose the correct unspecified or other-site code.
Coding tip
Verify the primary site and laterality in the oncology note before assigning C78.02.