C78.30

HCC Category Mapping

What This Code Means

Cancer that has spread to an unspecified part of the lungs or respiratory system from another location in the body.

Coding Tips

• •Use this code only when the specific respiratory organ cannot be identified; if known, use a more specific C78.3x code
• •Always code the primary cancer site separately and ensure documentation specifies this is metastatic disease

Clinical Significance

Secondary malignant neoplasm of an unspecified respiratory organ indicates metastatic cancer has spread to the respiratory system but the specific organ cannot be identified. This non-specific code should be used only as a last resort when documentation does not clarify whether the lung, pleura, mediastinum, or other respiratory structure is involved.

Documentation Requirements

• ✓Primary cancer site documented and coded separately
• ✓Best available description of the respiratory system involvement
• ✓Imaging reports should be reviewed for specific anatomical localization
• ✓Provider query initiated when documentation is insufficient for a more specific code
• ✓Clinical context — symptoms, imaging findings, treatment approach

Commonly Confused Codes