2027 ICD-10-CM Diagnosis Code C79.49Secondary malignant neoplasm of other parts of nervous system

ICD-10-CM Codes›C00–D49›C76-C80›C79

ICD-10-CM C79.49
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

C79.49 is a billable ICD-10-CM diagnosis code for secondary malignant neoplasm of other parts of nervous system. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 54 through 55. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 22 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Secondary malignancies.

For Medicare Advantage risk adjustment, C79.49 maps to CMS-HCC Category 17 (Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic) under the V28 model, adding a risk factor of about 4.209 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
C79.49
Billable Status
Yes — Valid for Submission
Code Describes
Secondary malignant neoplasm of other parts of nervous system
Short Description
Secondary malignant neoplasm of oth parts of nervous system
Parent Code
C79.4
Secondary malignant neoplasm of other and unspecified parts of nervous system

Code Classification

ChapterC00–D49Neoplasms
SectionC76-C80Malignant neoplasms of ill-defined, other secondary and unspecified sites
CategoryC79Secondary malignant neoplasm of other and unspecified sites
This CodeC79.49Secondary malignant neoplasm of other parts of nervous system

Medicare Risk Adjustment (HCC)Billing

C79.49 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 17— Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic
Payment HCC · PY 2027 one of 78 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+4.209
community, non-dual, aged · ranges 1.952–4.235 across segments
Hierarchy
Supersedes HCC 18, HCC 19, HCC 20, HCC 21, HCC 22, and HCC 23
less severe related categories are not paid alongside HCC 17
Prior Model (CMS-HCC V24)
HCC 8
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 8 · ESRD (V21): HCC 8 · ESRD (V24): HCC 8
ESRD V21 weights: 0.295 dialysis, 1.289–2.627 functioning graft · ESRD V24 weights: 0.353 dialysis, 1.571–3.226 functioning graft
Part D (RxHCC)
RxHCC 18 — Secondary Cancer of Lung, Liver, Brain, and Other Sites
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adenoid cystic carcinoma of lacrimal gland
  • Bilateral metastatic malignant neoplasm to eyes
  • Carcinoma ex pleomorphic adenoma of lacrimal gland
  • Disorder of olfactory nerve
  • Finding addressing invasion of optic nerve by tumor
  • Finding addressing invasion of sclera by tumor
  • Left lacrimal adenoid cystic carcinoma
  • Leukemic infiltrate of choroid
  • Leukemic infiltrate of retina
  • Leukemic infiltration of orbit
  • Malignant neoplasm of cauda equina
  • Malignant neoplasm of choroid
  • Malignant neoplasm of cornea
  • Malignant neoplasm of optic nerve
  • Malignant neoplasm of sclera
  • Malignant neoplasm of spinal meninges
  • Malignant neoplasm of vestibulocochlear nerve structure
  • Metastasis to nervous system and eye
  • Metastatic adenocarcinoma to retinal pigment epithelium
  • Metastatic adenoid cystic carcinoma to left lacrimal gland
  • Metastatic adenoid cystic carcinoma to right lacrimal gland
  • Metastatic carcinoma ex pleomorphic adenoma to lacrimal gland
  • Metastatic disseminated retinitis
  • Metastatic disseminated retinitis AND retinochoroiditis
  • Metastatic malignant neoplasm of meninges
  • Metastatic malignant neoplasm of peripheral nervous system
  • Metastatic malignant neoplasm of vestibulocochlear nerve
  • Metastatic malignant neoplasm to abducens nerve
  • Metastatic malignant neoplasm to accessory nerve
  • Metastatic malignant neoplasm to brain and spinal cord
  • Metastatic malignant neoplasm to cauda equina
  • Metastatic malignant neoplasm to choroid
  • Metastatic malignant neoplasm to ciliary body
  • Metastatic malignant neoplasm to conjunctiva
  • Metastatic malignant neoplasm to cornea
  • Metastatic malignant neoplasm to cranial nerve
  • Metastatic malignant neoplasm to eye
  • Metastatic malignant neoplasm to facial nerve
  • Metastatic malignant neoplasm to glossopharyngeal nerve
  • Metastatic malignant neoplasm to hypoglossal nerve
  • Metastatic malignant neoplasm to lacrimal drainage structure
  • Metastatic malignant neoplasm to lacrimal gland
  • Metastatic malignant neoplasm to lacrimal gland duct
  • Metastatic malignant neoplasm to left eye
  • Metastatic malignant neoplasm to leptomeninges
  • Metastatic malignant neoplasm to oculomotor nerve
  • Metastatic malignant neoplasm to olfactory nerve
  • Metastatic malignant neoplasm to optic nerve
  • Metastatic malignant neoplasm to orbit
  • Metastatic malignant neoplasm to retina
  • Metastatic malignant neoplasm to right eye
  • Metastatic malignant neoplasm to sclera
  • Metastatic malignant neoplasm to soft tissue of back
  • Metastatic malignant neoplasm to spinal cord
  • Metastatic malignant neoplasm to spinal meninges
  • Metastatic malignant neoplasm to trigeminal nerve
  • Metastatic malignant neoplasm to trochlear nerve
  • Metastatic malignant neoplasm to uveal tract
  • Metastatic malignant neoplasm to vagus nerve
  • Metastatic neuroblastoma
  • Metastatic neuroblastoma of orbit proper
  • Metastatic spinal cord compression
  • Myelopathy due to malignant neoplastic disease
  • Neoplasm of abducens nerve
  • Neoplasm of accessory nerve
  • Neoplasm of cauda equina
  • Neoplasm of facial nerve
  • Neoplasm of glossopharyngeal nerve
  • Neoplasm of hypoglossal nerve
  • Neoplasm of oculomotor nerve
  • Neoplasm of olfactory nerve
  • Neoplasm of sclera
  • Neoplasm of trigeminal nerve
  • Neoplasm of trochlear nerve
  • Neoplasm of vagus nerve
  • Perineural invasion by tumor present
  • Perineural invasion finding
  • Posterior uveitis due to infectious disease
  • Prostate cancer metastatic to eye
  • Retinal pigment epithelial adenocarcinoma
  • Right lacrimal adenoid cystic carcinoma
  • Spinal cord compression due to neoplasm
  • Structural abnormality of glossopharyngeal nerve
  • Tumor invades anterior chamber of eye
  • Tumor invades optic disc
  • Tumor invades optic nerve
  • Tumor invades optic nerve anterior to lamina cribrosa
  • Tumor invades optic nerve at lamina cribrosa
  • Tumor invades optic nerve posterior to lamina cribrosa but not to end of nerve
  • Tumor invades optic nerve to cut end of optic nerve
  • Tumor invades Schlemm's canal
  • Tumor invades sclera

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to C79.49: its own notes plus those printed at C79 and Chapter 2. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From C79 Secondary malignant neoplasm of other and unspecified sites applies to 25 codes
  • secondary carcinoid tumors (C7B.-)
  • secondary neuroendocrine tumors (C7B.-)

Notes

General instructions on how these codes are used.

From Chapter 2 (C00-D49) Neoplasms applies to 1,730 codes
  • Functional activity
  • All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
  • Morphology [Histology]
  • Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
  • Primary malignant neoplasms overlapping site boundaries
  • A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
  • Malignant neoplasm of ectopic tissue
  • Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name C79.49, its category, or a range that includes it.

Applicable To 2

These notes mention C79.49.

  • Z85.8 Personal history of malignant neoplasms of other organs and systems
    Conditions classifiable to C00-C14, C40-C49, C69-C75, C7A.098, C76-C79 names C76-C79, which includes this code
  • Z85.89 Personal history of malignant neoplasm of other organs and systems
    Conditions classifiable to C7A.098, C76, C77-C79 names C77-C79, which includes this code

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NEO070
Secondary malignancies
Default principal diagnosis: inpatient Yes · outpatient Yes

Table of NeoplasmsClinical

Anatomical sites in the Table of Neoplasms that reference this code family.

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
acoustic nerveC72.4C79.49–D33.3D43.3D49.7
arachnoidC70.9C79.49–D32.9D42.9D49.7
arachnoid › spinalC70.1C79.49–D32.1D42.1D49.7
auditory › nerveC72.4C79.49–D33.3D43.3D49.7
cauda equinaC72.1C79.49–D33.4D43.4D49.7
chiasma opticumC72.3C79.49–D33.3D43.3D49.7
choroidC69.3C79.49D09.2D31.3D48.7D49.81
ciliary bodyC69.4C79.49D09.2D31.4D48.7D49.89
conjunctivaC69.0C79.49D09.2D31.0D48.7D49.89
connective tissue NEC › orbitC69.6C79.49D09.2D31.6D48.1D49.89
conus medullarisC72.0C79.49–D33.4D43.4D49.7
cord (true) (vocal) › spinal (cervical) (lumbar) (thoracic)C72.0C79.49–D33.4D43.4D49.7
cornea (limbus)C69.1C79.49D09.2D31.1D48.7D49.89
cranial (fossa, any) › nerveC72.50C79.49–D33.3D43.3D49.7
cranial (fossa, any) › nerve › specified NECC72.59C79.49–D33.3D43.3D49.7
crystalline lensC69.4C79.49D09.2D31.4D48.7D49.89
dura (cranial) (mater)C70.9C79.49–D32.9D42.9D49.7
dura (cranial) (mater) › spinalC70.1C79.49–D32.1D42.1D49.7
epiduralC72.9C79.49–D33.9D43.9D49.7
extraduralC72.9C79.49–D33.9D43.9D49.7
extraocular muscleC69.6C79.49D09.2D31.6D48.7D49.89
eye NECC69.9C79.49D09.2D31.9D48.7D49.89
eyeballC69.9C79.49D09.2D31.9D48.7D49.89
filum terminaleC72.0C79.49–D33.4D43.4D49.7
ganglia [See Also: Neoplasm, nerve, peripheral] › cranial nerveC72.50C79.49–D33.3D43.3D49.7
intraocularC69.9C79.49D09.2D31.9D48.7D49.89
intraorbitalC69.6C79.49D09.2D31.6D48.7D49.89
irisC69.4C79.49D09.2D31.4D48.7D49.89
lacrimal › canaliculiC69.5C79.49D09.2D31.5D48.7D49.89
lacrimal › duct (nasal)C69.5C79.49D09.2D31.5D48.7D49.89
lacrimal › glandC69.5C79.49D09.2D31.5D48.7D49.89
lacrimal › punctumC69.5C79.49D09.2D31.5D48.7D49.89
lacrimal › sacC69.5C79.49D09.2D31.5D48.7D49.89
lens, crystallineC69.4C79.49D09.2D31.4D48.7D49.89
limbus of corneaC69.1C79.49D09.2D31.1D48.7D49.89
meningesC70.9C79.49–D32.9D42.9D49.7
meninges › spinal (cord)C70.1C79.49–D32.1D42.1D49.7
motor tractC72.9C79.49–D33.9D43.9D49.7
motor tract › cauda equinaC72.1C79.49–D33.4D43.4D49.7
motor tract › spinalC72.0C79.49–D33.4D43.4D49.7
muscle [See Also: Neoplasm, connective tissue] › extraocularC69.6C79.49D09.2D31.6D48.7D49.89
nasolacrimal ductC69.5C79.49D09.2D31.5D48.7D49.89
nerve (ganglion) › abducensC72.59C79.49–D33.3D43.3D49.7
nerve (ganglion) › accessory (spinal)C72.59C79.49–D33.3D43.3D49.7
nerve (ganglion) › acousticC72.4C79.49–D33.3D43.3D49.7
nerve (ganglion) › auditoryC72.4C79.49–D33.3D43.3D49.7
nerve (ganglion) › cranialC72.50C79.49–D33.3D43.3D49.7
nerve (ganglion) › cranial › specified NECC72.59C79.49–D33.3D43.3D49.7
nerve (ganglion) › facialC72.59C79.49–D33.3D43.3D49.7
nerve (ganglion) › glossopharyngealC72.59C79.49–D33.3D43.3D49.7
nerve (ganglion) › hypoglossalC72.59C79.49–D33.3D43.3D49.7
nerve (ganglion) › oculomotorC72.59C79.49–D33.3D43.3D49.7
nerve (ganglion) › olfactoryC47.2C79.49–D33.3D43.3D49.7
nerve (ganglion) › opticC72.3C79.49–D33.3D43.3D49.7
nerve (ganglion) › peripheral NEC › orbitC69.6C79.49–D31.6D48.7D49.2
nerve (ganglion) › spinal NEC › accessoryC72.59C79.49–D33.3D43.3D49.7
nerve (ganglion) › trigeminalC72.59C79.49–D33.3D43.3D49.7
nerve (ganglion) › trochlearC72.59C79.49–D33.3D43.3D49.7
nerve (ganglion) › vagusC72.59C79.49–D33.3D43.3D49.7
nervous system (central) › specified site NEC–C79.49–D33.7D43.8–
olfactory nerve or bulbC72.2C79.49–D33.3D43.3D49.7
optic nerve, chiasm, or tractC72.3C79.49–D33.3D43.3D49.7
orbitC69.6C79.49D09.2D31.6D48.7D49.89
orbit › autonomic nerveC69.6C79.49–D31.6D48.7D49.2
orbit › eyeC69.6C79.49D09.2D31.6D48.7D49.89
orbit › peripheral nervesC69.6C79.49–D31.6D48.7D49.2
orbit › soft partsC69.6C79.49D09.2D31.6D48.7D49.89
parasellarC72.9C79.49–D33.9D43.8D49.7
pia mater › spinalC70.1C79.49–D32.1D42.1D49.7
retinaC69.2C79.49D09.2D31.2D48.7D49.81
retrobulbarC69.6C79.49–D31.6D48.7D49.89
scleraC69.4C79.49D09.2D31.4D48.7D49.89
spine, spinal (column) › cord (cervical) (lumbar) (sacral) (thoracic)C72.0C79.49–D33.4D43.4D49.7
spine, spinal (column) › dura materC70.1C79.49–D32.1D42.1D49.7
spine, spinal (column) › membraneC70.1C79.49–D32.1D42.1D49.7
spine, spinal (column) › meningesC70.1C79.49–D32.1D42.1D49.7
spine, spinal (column) › pia materC70.1C79.49–D32.1D42.1D49.7
uveal tractC69.4C79.49D09.2D31.4D48.7D49.89

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Convert C79.49 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
198.4 Sec malig neo nerve NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About C79.49Overview

What is the ICD-10 code for secondary malignant neoplasm of other parts of nervous system?

The ICD-10-CM code for secondary malignant neoplasm of other parts of nervous system is C79.49 (sometimes written as C7949). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is C79.49 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report secondary malignant neoplasm of other parts of nervous system on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does C79.49 group to?

When secondary malignant neoplasm of other parts of nervous system is the principal diagnosis on an inpatient stay, it groups to MS-DRG 55, 54, with relative weights from 1.0291 to 1.5197 depending on complications. Higher weights mean higher Medicare reimbursement.

Is C79.49 a CC or MCC?

CMS lists C79.49 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 22 closely related codes in its exclusion list.

Can C79.49 be reported with a code from C7B?

Not as a rule. The Excludes1 note at C79, which applies to C79.49, lists "secondary carcinoid tumors (C7B.-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What HCC is C79.49?

C79.49 (secondary malignant neoplasm of other parts of nervous system) maps to CMS-HCC Category 17 (Cancer Metastatic to Lung, Liver, Brain, and Other Organs; Acute Myeloid Leukemia Except Promyelocytic), commonly written as HCC 17, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 8 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 18.

Does C79.49 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, C79.49 adds a risk adjustment factor of about 4.209 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 1.952 to 4.235 depending on the payment segment). HCC 17 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 17 category page.