C79.40
BillableSecondary malignant neoplasm of unspecified part of nervous system
HCC Category Mapping
V28HCC 17 — Metastatic Cancer and Acute Leukemia
0.368V24HCC 8 — Metastatic Cancer and Acute Leukemia
2.484ESRDHCC 8 — Metastatic Cancer and Acute Leukemia
0.000RxHCCHCC 18 — Metastatic Cancer to Lung and Other Respiratory Sites
0.000What This Code Means
Cancer that has spread to the nervous system (brain, spinal cord, or nerves) but the specific location within the nervous system is not identified.
Coding Tips
- •Use this code only when the specific site of nervous system involvement cannot be determined; if location is known, use more specific codes (C79.31 for brain, C79.32 for meninges, C79.49 for other sites)
- •Query the provider for clarification on the exact location of nervous system involvement to enable more precise coding
Clinical Significance
Secondary malignant neoplasm of an unspecified part of the nervous system indicates cancer has metastasized to the nervous system but the exact location (brain, meninges, spinal cord, peripheral nerves) is not documented. This non-specific code should prompt a provider query since the specific nervous system site significantly impacts treatment decisions and prognosis.
Documentation Requirements
- ✓Primary cancer site documented and coded separately
- ✓Best available description of the nervous system involvement
- ✓Imaging (MRI brain and/or spine) or cerebrospinal fluid analysis
- ✓Provider query documenting attempt to clarify the specific nervous system site
- ✓Neurological symptoms and examination findings
Commonly Confused Codes
C79.31 — Secondary malignant neoplasm of brain; use when brain is the documented siteC79.32 — Secondary malignant neoplasm of cerebral meninges; use when meningeal disease is documentedC79.49 — Secondary malignant neoplasm of other parts of nervous system; use when spinal cord or peripheral nerves are identifiedC72.0-C72.9 — Primary malignant neoplasm of spinal cord, cranial nerves, other CNS; distinguish primary from secondary
Code Hierarchy
└C79Secondary malignant neoplasm of other and unspecified sites└C79.4Secondary malignant neoplasm of other and unspecified parts of nervous system└C79.40Secondary malignant neoplasm of unspecified part of nervous system
└C79.40Secondary malignant neoplasm of unspecified part of nervous system