2024 ICD-10-CM Diagnosis Code C79.40

Secondary malignant neoplasm of unspecified part of nervous system

ICD-10-CM Code:
ICD-10 Code for:
Secondary malignant neoplasm of unsp part of nervous system
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Code Navigator:

Code Classification

  • Neoplasms
    • Malignant neoplasms of ill-defined, other secondary and unspecified sites
      • Secondary malignant neoplasm of other and unspecified sites

C79.40 is a billable diagnosis code used to specify a medical diagnosis of secondary malignant neoplasm of unspecified part of nervous system. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

The following anatomical sites found in the Table of Neoplasms reference this diagnosis code given the correct histological behavior: Neoplasm, neoplastic central nervous system or Neoplasm, neoplastic nervous system (central) or Neoplasm, neoplastic pia mater .

Unspecified diagnosis codes like C79.40 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Metastasis to peripheral nerve
  • Metastatic malignant neoplasm to central nervous system
  • Metastatic malignant neoplasm to nervous system
  • Metastatic neuroblastoma
  • Metastatic neuroblastoma to central nervous system
  • Neuroblastoma of central nervous system

Clinical Classification

Clinical Information

  • AIDS Arteritis, Central Nervous System

    inflammation of arteries in the central nervous system that occurs in patients with acquired immunodeficiency syndrome or aids-related opportunistic infections.
  • Brain Diseases

    pathologic conditions affecting the brain, which is composed of the intracranial components of the central nervous system. this includes (but is not limited to) the cerebral cortex; intracranial white matter; basal ganglia; thalamus; hypothalamus; brain stem; and cerebellum.
  • Brain Diseases, Metabolic

    acquired or inborn metabolic diseases that produce brain dysfunction or damage. these include primary (i.e., disorders intrinsic to the brain) and secondary (i.e., extracranial) metabolic conditions that adversely affect cerebral function.
  • Brain Diseases, Metabolic, Inborn

    brain disorders resulting from inborn metabolic errors, primarily from enzymatic defects which lead to substrate accumulation, product reduction, or increase in toxic metabolites through alternate pathways. the majority of these conditions are familial, however spontaneous mutation may also occur in utero.
  • Central Nervous System

    the main information-processing organs of the nervous system, consisting of the brain, spinal cord, and meninges.
  • Central Nervous System Agents

    a class of drugs producing both physiological and psychological effects through a variety of mechanisms. they can be divided into "specific" agents, e.g., affecting an identifiable molecular mechanism unique to target cells bearing receptors for that agent, and "nonspecific" agents, those producing effects on different target cells and acting by diverse molecular mechanisms. those with nonspecific mechanisms are generally further classed according to whether they produce behavioral depression or stimulation. those with specific mechanisms are classed by locus of action or specific therapeutic use. (from gilman ag, et al., goodman and gilman's the pharmacological basis of therapeutics, 8th ed, p252)
  • Central Nervous System Bacterial Infections

    bacterial infections of the brain, spinal cord, and meninges, including infections involving the perimeningeal spaces.
  • Central Nervous System Cysts

    congenital or acquired cysts of the brain, spinal cord, or meninges which may remain stable in size or undergo progressive enlargement.
  • Central Nervous System Depressants

    a very loosely defined group of drugs that tend to reduce the activity of the central nervous system. the major groups included here are ethyl alcohol, anesthetics, hypnotics and sedatives, narcotics, and tranquilizing agents (antipsychotics and antianxiety agents).
  • Central Nervous System Diseases

    diseases of any component of the brain (including the cerebral hemispheres, diencephalon, brain stem, and cerebellum) or the spinal cord.
  • Central Nervous System Fungal Infections

    mycoses of the brain, spinal cord, and meninges which may result in encephalitis; meningitis, fungal; myelitis; brain abscess; and epidural abscess. certain types of fungi may produce disease in immunologically normal hosts, while others are classified as opportunistic pathogens, causing illness primarily in immunocompromised individuals (e.g., acquired immunodeficiency syndrome).
  • Central Nervous System Helminthiasis

    infections of the brain; spinal cord; or meninges caused by helminths (parasitic worms).
  • Central Nervous System Infections

    pathogenic infections of the brain, spinal cord, and meninges. dna virus infections; rna virus infections; bacterial infections; mycoplasma infections; spirochaetales infections; fungal infections; protozoan infections; helminthiasis; and prion diseases may involve the central nervous system as a primary or secondary process.
  • Central Nervous System Neoplasms

    benign and malignant neoplastic processes that arise from or secondarily involve the brain, spinal cord, or meninges.
  • Central Nervous System Parasitic Infections

    infections of the brain, spinal cord, and meninges caused by parasites.
  • Central Nervous System Protozoal Infections

    infections of the brain, spinal cord, or meninges by single celled organisms of the former subkingdom known as protozoa. the central nervous system may be the primary or secondary site of protozoal infection. these diseases may occur as opportunistic infections or arise in immunocompetent hosts.
  • Central Nervous System Sensitization

    an increased response to stimulation that is mediated by amplification of signaling in the central nervous system (cns).
  • Central Nervous System Stimulants

    a loosely defined group of drugs that tend to increase behavioral alertness, agitation, or excitation. they work by a variety of mechanisms, but usually not by direct excitation of neurons. the many drugs that have such actions as side effects to their main therapeutic use are not included here.
  • Central Nervous System Vascular Malformations

    congenital, inherited, or acquired abnormalities involving arteries; veins; or venous sinuses in the brain; spinal cord; and meninges.
  • Central Nervous System Venous Angioma

    a vascular anomaly characterized by a radial or wedge-shaped arrangement of dilated veins draining into a larger vein in the brain, spinal cord, or the meninges. veins in a venous angioma are surrounded by normal nervous tissue, unlike a central nervous system cavernous hemangioma that lacks intervening nervous tissue. drainage of venous angioma is fully integrated with the body's venous system, therefore, in most cases there is no clinical signs and rare bleeding.
  • Central Nervous System Viral Diseases

    viral infections of the brain, spinal cord, meninges, or perimeningeal spaces.
  • Cerebral Phaeohyphomycosis

    cns infections caused by neurotropic dematiaceous fungi that contain melanin in their cell walls. the infections often result in brain abscess; encephalitis; and meningitis in patients who are often immunocompetent. the common causative fungi include members cladophialophora bantiana, exophiala dermatitidis, rhinocladiella mackenziei, and ochroconis gallopavum. r. mackenziei infection is seen almost exclusively in patients from the middle east.
  • Hemangioma, Cavernous, Central Nervous System

    a vascular anomaly composed of a collection of large, thin walled tortuous veins that can occur in any part of the central nervous system but lack intervening nervous tissue. familial occurrence is common and has been associated with a number of genes mapped to 7q, 7p and 3q. clinical features include seizures; headache; stroke; and progressive neurological deficit.
  • Hereditary Central Nervous System Demyelinating Diseases

    inherited conditions characterized by a loss of myelin in the central nervous system.
  • Lupus Vasculitis, Central Nervous System

    central nervous system vasculitis that is associated with systemic lupus erythematosus. clinical manifestations may include dementia; seizures; cranial nerve diseases; hemiparesis; blindness; dysphasia; and other neurological disorders.
  • Lyme Neuroborreliosis

    nervous system infections caused by tick-borne spirochetes of the borrelia burgdorferi group. the disease may affect elements of the central or peripheral nervous system in isolation or in combination. common clinical manifestations include a lymphocytic meningitis, cranial neuropathy (most often a facial neuropathy), polyradiculopathy, and a mild loss of memory and other cognitive functions. less often more extensive inflammation involving the central nervous system (encephalomyelitis) may occur. in the peripheral nervous system, b. burgdorferi infection is associated with mononeuritis multiplex and polyradiculoneuritis. (from j neurol sci 1998 jan 8;153(2):182-91)
  • Neurocysticercosis

    infection of the brain, spinal cord, or perimeningeal structures with the larval forms of the genus taenia (primarily t. solium in humans). lesions formed by the organism are referred to as cysticerci. the infection may be subacute or chronic, and the severity of symptoms depends on the severity of the host immune response and the location and number of lesions. seizures represent the most common clinical manifestation although focal neurologic deficits may occur. (from joynt, clinical neurology, 1998, ch27, pp46-50)
  • Neuroschistosomiasis

    schistosomiasis of the brain, spinal cord, or meninges caused by infections with trematodes of the genus schistosoma (primarily schistosoma japonicum; schistosoma mansoni; and schistosoma haematobium in humans). s. japonicum infections of the nervous system may cause an acute meningoencephalitis or a chronic encephalopathy. s. mansoni and s. haematobium nervous system infections are associated with acute transverse myelitis involving the lower portions of the spinal cord. (from joynt, clinical neurology, 1998, ch27, pp61-2)
  • Neurosyphilis

    infections of the central nervous system caused by treponema pallidum which present with a variety of clinical syndromes. the initial phase of infection usually causes a mild or asymptomatic meningeal reaction. the meningovascular form may present acutely as brain infarction. the infection may also remain subclinical for several years. late syndromes include general paresis; tabes dorsalis; meningeal syphilis; syphilitic optic atrophy; and spinal syphilis. general paresis is characterized by progressive dementia; dysarthria; tremor; myoclonus; seizures; and argyll-robertson pupils. (adams et al., principles of neurology, 6th ed, pp722-8)
  • Toxoplasmosis, Cerebral

    infections of the brain caused by the protozoan toxoplasma gondii that primarily arise in individuals with immunologic deficiency syndromes (see also aids-related opportunistic infections). the infection may involve the brain diffusely or form discrete abscesses. clinical manifestations include seizures, altered mentation, headache, focal neurologic deficits, and intracranial hypertension. (from joynt, clinical neurology, 1998, ch27, pp41-3)
  • Tuberculosis, Central Nervous System

    tuberculosis of the brain, spinal cord, or meninges (tuberculosis, meningeal), most often caused by mycobacterium tuberculosis and rarely by mycobacterium bovis. the infection may be limited to the nervous system or coexist in other organs (e.g., tuberculosis, pulmonary). the organism tends to seed the meninges causing a diffuse meningitis and leads to the formation of tuberculoma, which may occur within the brain, spinal cord, or perimeningeal spaces. tuberculous involvement of the vertebral column (tuberculosis, spinal) may result in nerve root or spinal cord compression. (from adams et al., principles of neurology, 6th ed, pp717-20)
  • Vasculitis, Central Nervous System

    inflammation of blood vessels within the central nervous system. primary vasculitis is usually caused by autoimmune or idiopathic factors, while secondary vasculitis is caused by existing disease process. clinical manifestations are highly variable but include headache; seizures; behavioral alterations; intracranial hemorrhages; transient ischemic attack; and brain infarction. (from adams et al., principles of neurology, 6th ed, pp856-61)
  • Vertigo

    an illusion of movement, either of the external world revolving around the individual or of the individual revolving in space. vertigo may be associated with disorders of the inner ear (ear, inner); vestibular nerve; brainstem; or cerebral cortex. lesions in the temporal lobe and parietal lobe may be associated with focal seizures that may feature vertigo as an ictal manifestation. (from adams et al., principles of neurology, 6th ed, pp300-1)
  • Pia Mater

    the innermost layer of the three meninges covering the brain and spinal cord. it is the fine vascular membrane that lies under the arachnoid and the dura mater.
  • Metastatic Neuroblastoma

    a neuroblastoma that has metastasized from its original site of growth to another anatomic site.

Convert C79.40 to ICD-9-CM

  • ICD-9-CM Code: 198.4 - Sec malig neo nerve NEC
    Approximate Flag - The approximate mapping means there is not an exact match between the ICD-10 and ICD-9 codes and the mapped code is not a precise representation of the original code.

Table of Neoplasms

This code is referenced in the table of neoplasms by anatomical site. For each site there are six possible code numbers according to whether the neoplasm in question is malignant, benign, in situ, of uncertain behavior, or of unspecified nature. The description of the neoplasm will often indicate which of the six columns is appropriate.

Where such descriptors are not present, the remainder of the Index should be consulted where guidance is given to the appropriate column for each morphological (histological) variety listed. However, the guidance in the Index can be overridden if one of the descriptors mentioned above is present.

Neoplasm, neoplastic Malignant
CaInSitu Benign Uncertain
»Neoplasm, neoplastic
  »central nervous system
»Neoplasm, neoplastic
  »nervous system (central)
C72.9C79.40 D33.9D43.9D49.7
»Neoplasm, neoplastic
  »pia mater
C70.9C79.40 D32.9D42.9D49.7

Patient Education


Cancer begins in your cells, which are the building blocks of your body. Normally, your body forms new cells as you need them, replacing old cells that die. Sometimes this process goes wrong. New cells grow even when you don't need them, and old cells don't die when they should. These extra cells can form a mass called a tumor. Tumors can be benign or malignant. Benign tumors aren't cancer while malignant ones are. Cells from malignant tumors can invade nearby tissues. They can also break away and spread to other parts of the body.

Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for where they start. For example, lung cancer starts in the lung, and breast cancer starts in the breast. The spread of cancer from one part of the body to another is called metastasis. Symptoms and treatment depend on the cancer type and how advanced it is. Most treatment plans may include surgery, radiation and/or chemotherapy. Some may involve hormone therapy, immunotherapy or other types of biologic therapy, or stem cell transplantation.

NIH: National Cancer Institute

[Learn More in MedlinePlus]

Neurologic Diseases

The brain, spinal cord, and nerves make up the nervous system. Together they control all the workings of the body. When something goes wrong with a part of your nervous system, you can have trouble moving, speaking, swallowing, breathing, or learning. You can also have problems with your memory, senses, or mood.

There are more than 600 neurologic diseases. Major types include:

  • Diseases caused by faulty genes, such as Huntington's disease and muscular dystrophy
  • Problems with the way the nervous system develops, such as spina bifida
  • Degenerative diseases, where nerve cells are damaged or die, such as Parkinson's disease and Alzheimer's disease
  • Diseases of the blood vessels that supply the brain, such as stroke
  • Injuries to the spinal cord and brain
  • Seizure disorders, such as epilepsy
  • Cancer, such as brain tumors
  • infections, such as meningitis

[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.


[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.