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C79.49 ICD-10-CM Code: Secondary malignant neoplasm of other parts of nervous system

C79.49 maps to CMS-HCC V28 17. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software

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Code lookupC79.49

FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of ill-defined, other secondary and unspecified sites (C76-C80)

C79.49

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Secondary malignant neoplasm of other parts of nervous system

Cancer that has spread to other parts of the nervous system not specified elsewhere, such as the spinal cord or peripheral nerves.

Buddy the Bee presenting code insight

Buddy Insight

Secondary malignant neoplasm of other parts of the nervous system captures metastatic disease to nervous system structures beyond the brain and cerebral meninges, including the spinal cord, spinal meninges, cranial nerves, and peripheral nerves.

OverviewRisk ModelsCode BookDocumentationAuditNotesEdition comparison

CMS-HCC V28

HCC 17

Coefficient HCC 17: 4.209 (Community Non-Dual Aged (CNA))

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 008

Code-level coefficient reference

ESRD/PACE

HCC 8

Code-level coefficient reference

RXHCC

HCC 18

Code-level coefficient reference

Code Book Path

Official
C79Secondary malignant neoplasm of other and unspecified sitesC79.4Secondary malignant neoplasm of other and unspecified parts of nervous systemC79.49Secondary malignant neoplasm of other parts of nervous system

Inclusion Terms

Official

No inclusion terms are included in this display for C79.49. Check the code and parent instructions in the Code Book.

Excludes 2

Official

No Excludes 2 notes are included in this display for C79.49. Check the code and parent instructions in the Code Book.

Related Codes

Official
C79.40Secondary malignant neoplasm of unspecified part of nervous system

Includes

Official

No Includes notes are included in this display for C79.49. Check the code and parent instructions in the Code Book.

Excludes 1

Official
  • secondary carcinoid tumors (C7B.-)Inherited from C79
  • secondary neuroendocrine tumors (C7B.-)Inherited from C79

Code First

Official

No Code First sequencing instructions are included in this display for C79.49. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for C79.49. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for C79.49. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance
Primary cancer site documented and coded separately
Specific identification of the nervous system structure — spinal cord, spinal meninges, cranial nerves, peripheral nerves
MRI of the spine or affected region confirming metastatic disease
Neurological assessment — motor function, sensation, bowel/bladder function

MEAT Support

HCC Buddy guidance
Primary cancer site documented and coded separately
Specific identification of the nervous system structure — spinal cord, spinal meninges, cranial nerves, peripheral nerves
MRI of the spine or affected region confirming metastatic disease
Neurological assessment — motor function, sensation, bowel/bladder function

Audit Caution

HCC Buddy guidance
Using C79.49 for brain metastases when C79.31 specifically exists
Not recognizing spinal cord compression as a medical emergency requiring additional coding (G95.20)
Confusing primary spinal cord tumors (ependymoma, astrocytoma) with metastatic spinal disease
Failing to code associated neurological deficits separately — paraplegia, neurogenic bladder

Common Mistakes

HCC Buddy guidance
C79.31 — Secondary malignant neoplasm of brain; brain metastases have their own specific code
C79.32 — Secondary malignant neoplasm of cerebral meninges; cerebral meningeal disease is coded separately
C79.40 — Secondary malignant neoplasm of unspecified nervous system; use C79.49 when the specific site is known
C72.0-C72.1 — Primary malignant neoplasm of spinal cord; distinguish primary from metastatic spinal tumors

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is C79.49 an HCC code?

Yes. C79.49 (Secondary malignant neoplasm of other parts of nervous system) maps to HCC 17, Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 4.209. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: C79.49 is billable and maps to V28 HCC 17, Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
C79.49
Description
Secondary malignant neoplasm of other parts of nervous system
HCC (V28)
HCC 17 — Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic
RAF reference coefficient
4.209
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 17, Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic
4.209
ESRDHCC 8, Metastatic Cancer and Acute Leukemia
Not separately weighted
RxHCCHCC 18, Secondary Cancer of Lung, Liver, Brain, and Other Sites
Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work C79.49 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for C79.49

For C79.49, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

  • MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
  • EEvaluate: test results, medication response, or physical findings reviewed by the provider
  • AAssess: explicit mention in the assessment or plan with acknowledgment of status
  • TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Coder workflow notes

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What This Code Means

C79.49 is the ICD-10-CM diagnosis code for secondary malignant neoplasm of other parts of nervous system. Cancer that has spread to other parts of the nervous system not specified elsewhere, such as the spinal cord or peripheral nerves. C79.49 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of ill-defined, other secondary and unspecified sites (c76-c80).

Under the CMS-HCC V28 risk adjustment model, C79.49 maps to Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic (HCC 17) with a source-labeled community, non-dual, aged reference coefficient of 4.209. No V24 mapping is shown for C79.49; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

This is a catch-all code for secondary nervous system malignancies not captured by C79.31 (brain) or C79.32 (meninges); document the specific site when possible. For C79.49, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for C79.49 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •This is a catch-all code for secondary nervous system malignancies not captured by C79.31 (brain) or C79.32 (meninges); document the specific site when possible
  • •Ensure the primary cancer site is coded separately and that more specific nervous system sites have been ruled out

Clinical Significance

Secondary malignant neoplasm of other parts of the nervous system captures metastatic disease to nervous system structures beyond the brain and cerebral meninges, including the spinal cord, spinal meninges, cranial nerves, and peripheral nerves. Spinal cord metastases can cause devastating neurological complications including paralysis and require urgent treatment.

Documentation Requirements

  • ✓Primary cancer site documented and coded separately
  • ✓Specific identification of the nervous system structure — spinal cord, spinal meninges, cranial nerves, peripheral nerves
  • ✓MRI of the spine or affected region confirming metastatic disease
  • ✓Neurological assessment — motor function, sensation, bowel/bladder function
  • ✓Urgency of intervention — spinal cord compression is a medical emergency

Commonly Confused Codes

  • •C79.31: Secondary malignant neoplasm of brain; brain metastases have their own specific code
  • •C79.32: Secondary malignant neoplasm of cerebral meninges; cerebral meningeal disease is coded separately
  • •C79.40: Secondary malignant neoplasm of unspecified nervous system; use C79.49 when the specific site is known
  • •C72.0-C72.1: Primary malignant neoplasm of spinal cord; distinguish primary from metastatic spinal tumors

Child Codes

C79.40Secondary malignant neoplasm of unspecified part of nervous system
HCC 17
C79.49Secondary malignant neoplasm of other parts of nervous system
HCC 17

Code Hierarchy

└C79Secondary malignant neoplasm of other and unspecified sites└C79.4Secondary malignant neoplasm of other and unspecified parts of nervous system└C79.49Secondary malignant neoplasm of other parts of nervous system
└C79.49Secondary malignant neoplasm of other parts of nervous system

Also searched as

  • C79 49
  • C7949

For C79.49, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

C79.49 maps to CMS-HCC V28 category 17, Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for C79.49. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

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