ICD-10 Code C78.39 – Secondary malignant neoplasm of other respiratory organs (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C78.39 – Secondary malignant neoplasm of other respiratory organs
What it is
C78.39 identifies metastatic cancer in a respiratory organ other than the lung, pleura, or mediastinum. Use it when documentation states a secondary malignant neoplasm in another specified respiratory site.
Clinical signs
Clinical features vary; refer to documentation. Findings may reflect the involved respiratory structure, such as cough, dyspnea, hemoptysis, or imaging evidence of a metastatic lesion.
When to use this code
Use this code when the record clearly documents secondary malignant involvement of a non-lung respiratory organ. It is appropriate for metastatic disease confirmed by imaging, pathology, or oncology assessment. If the site is not specified, check documentation before coding.
Do not use for
Do not use this code for primary respiratory cancers or metastases to the lung, pleura, or mediastinum. If the exact respiratory site is unclear, check documentation.
Coding tip
Confirm the primary cancer site and the exact metastatic respiratory organ before assigning C78.39.