ICD-10 Code C78.2 – Secondary malignant neoplasm of pleura (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C78.2 – Secondary malignant neoplasm of pleura
What it is
C78.2 identifies metastatic cancer involving the pleura, the thin lining around the lungs. Use it when a primary malignancy has spread to the pleural surface.
Clinical signs
Clinical features vary; refer to documentation. Common findings include pleural effusion, chest discomfort, shortness of breath, or imaging evidence of pleural masses or nodularity.
When to use this code
Use C78.2 when the record clearly states secondary malignant neoplasm of pleura, pleural metastasis, or metastatic involvement of the pleura. It applies when the pleura is the documented site of spread, even if the primary cancer is coded separately. Check documentation if the note only says malignant pleural effusion without confirming metastatic disease.
Do not use for
Do not use this code for primary pleural tumors or for pleural effusion without documented malignancy. If the site is described only as lung, chest wall, or unspecified thoracic involvement, check documentation.
Coding tip
Code the primary cancer first when it is still active, then add C78.2 for the pleural metastasis.