C80.0

HCC Category Mapping

What This Code Means

Cancer that has spread throughout the body in multiple locations, but the original source or type cannot be determined.

Coding Tips

• •Use only when disseminated cancer is documented but primary site is unknown or unspecified
• •This is a non-specific code; attempt to identify primary site before using this code

Clinical Significance

Disseminated malignant neoplasm, unspecified represents widespread cancer throughout the body where neither the primary site nor the specific cancer type can be determined. This diagnosis carries an extremely poor prognosis and reflects a patient with high care needs including pain management, nutritional support, and often palliative or hospice-level services. It indicates that despite diagnostic workup, the cancer origin remains unknown.

Documentation Requirements

• ✓Documentation confirming disseminated (widespread) malignancy
• ✓Record of diagnostic workup performed to attempt to identify primary site and cancer type
• ✓Explanation for why the primary site cannot be determined (cancer of unknown primary)
• ✓Sites of metastatic disease documented
• ✓Performance status and treatment plan (curative intent vs palliative)
• ✓Palliative care or hospice referral documentation if applicable

Commonly Confused Codes