2026 ICD-10-CM Diagnosis Code C71.9Malignant neoplasm of brain, unspecified

ICD-10-CM Codes›C00–D49›C69-C72›C71

ICD-10-CM C71.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

C71.9 is a billable ICD-10-CM diagnosis code for malignant neoplasm of brain, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nervous system cancers - brain.

Code Identity

ICD-10-CM Code
C71.9
Billable Status
Yes — Valid for Submission
Code Describes
Malignant neoplasm of brain, unspecified
Short Description
Malignant neoplasm of brain, unspecified
Same as the full description in the CMS dataset.
Parent Code
C71
Malignant neoplasm of brain

Code Classification

ChapterC00–D49Neoplasms
SectionC69-C72Malignant neoplasms of eye, brain and other parts of central nervous system
CategoryC71Malignant neoplasm of brain
This CodeC71.9Malignant neoplasm of brain, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Anaplastic astrocytoma of brain
  • Anaplastic astrocytoma of central nervous system
  • Anaplastic glioma of brain
  • Astroblastoma of brain
  • Astroblastoma of central nervous system
  • Astrocytoma of brain
  • Carcinoma of brain
  • Dementia due to primary malignant neoplasm of brain
  • Desmoplastic nodular medulloblastoma of brain
  • Diffuse astrocytoma of brain
  • Embryonal carcinoma
  • Ependymoblastoma
  • Ependymoma
  • Ependymoma of brain
  • Fibrillary astrocytoma of brain
  • Fibrillary astrocytoma of central nervous system
  • Ganglioneuroblastoma
  • Ganglioneuroblastoma of central nervous system
  • Gemistocytic astrocytoma of brain
  • Gemistocytic astrocytoma of central nervous system
  • Germ cell tumor of the brain
  • Giant cell glioblastoma of brain
  • Giant cell glioblastoma of central nervous system
  • Glial tumor of brain
  • Glioblastoma multiforme
  • Glioblastoma multiforme of brain
  • Gliosarcoma of brain
  • Gliosarcoma of central nervous system
  • Grade 4 malignant glioma of brain
  • High grade astrocytoma of brain
  • Large cell medulloblastoma of brain
  • Low grade astrocytoma of brain
  • Low grade glioma of brain
  • Low grade malignant glioma of brain
  • Malignant glioma of brain
  • Malignant neoplasm of axial suprasellar region of brain
  • Malignant neoplasm of brain
  • Malignant teratoma
  • Medulloblastoma
  • Mixed glial tumor of brain
  • Mixed glioma
  • Mixed oligoastrocytoma
  • Neoplasm of pituitary and suprasellar region
  • Neuroblastoma of brain
  • Neuroblastoma of central nervous system
  • Oligodendroglioma
  • Oligodendroglioma of brain
  • Pilomyxoid astrocytoma
  • Pilomyxoid astrocytoma of brain
  • Pleomorphic xanthoastrocytoma
  • Pleomorphic xanthoastrocytoma of brain
  • Primary anaplastic astrocytoma of brain
  • Primary anaplastic astrocytoma of central nervous system
  • Primary anaplastic glioma of brain
  • Primary anaplastic large cell medulloblastoma of brain
  • Primary astroblastoma of brain
  • Primary astroblastoma of central nervous system
  • Primary desmoplastic nodular medulloblastoma of brain
  • Primary diffuse astrocytoma of brain
  • Primary embryonal carcinoma of brain
  • Primary ependymoblastoma
  • Primary fibrillary astrocytoma of brain
  • Primary fibrillary astrocytoma of central nervous system
  • Primary ganglioneuroblastoma
  • Primary ganglioneuroblastoma of brain
  • Primary ganglioneuroblastoma of central nervous system
  • Primary gemistocytic astrocytoma of brain
  • Primary gemistocytic astrocytoma of central nervous system
  • Primary giant cell glioblastoma of brain
  • Primary giant cell glioblastoma of central nervous system
  • Primary glioblastoma multiforme of brain
  • Primary gliosarcoma of brain
  • Primary gliosarcoma of central nervous system
  • Primary large cell medulloblastoma of brain
  • Primary malignant astrocytoma of brain
  • Primary malignant atypical teratoid rhabdoid neoplasm of brain
  • Primary malignant atypical teratoid rhabdoid neoplasm of central nervous system
  • Primary malignant glioma of brain
  • Primary malignant neoplasm of brain
  • Primary medulloblastoma
  • Primary mixed glioma
  • Primary mixed oligoastrocytoma
  • Primary neuroblastoma
  • Primary neuroblastoma of brain
  • Primary neuroblastoma of central nervous system
  • Primary oligodendroglioma
  • Primary oligodendroglioma of brain
  • Primary pilomyxoid astrocytoma
  • Primary pilomyxoid astrocytoma of brain
  • Primary pleomorphic xanthoastrocytoma of brain
  • Primary primitive neuroectodermal tumor
  • Primary protoplasmic astrocytoma of brain
  • Primary teratoma of brain
  • Primitive neuroectodermal tumor
  • Protoplasmic astrocytoma of brain
  • RELA fusion-positive supratentorial ependymoma
  • Suprasellar germ cell tumor

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Astroblastoma
      • unspecified site
    • Astrocytoma(cystic)
      • anaplastic
        • unspecified site
    • Astrocytoma(cystic)
      • fibrillary
        • unspecified site
    • Astrocytoma(cystic)
      • fibrous
        • unspecified site
    • Astrocytoma(cystic)
      • gemistocytic
        • unspecified site
    • Astrocytoma(cystic)
      • juvenile
        • unspecified site
    • Astrocytoma(cystic)
      • pilocytic
        • unspecified site
    • Astrocytoma(cystic)
      • piloid
        • unspecified site
    • Astrocytoma(cystic)
      • protoplasmic
        • unspecified site
    • Astrocytoma(cystic)
      • unspecified site
    • Astroglioma
      • unspecified site
    • Ependymoblastoma
      • unspecified site
    • Ependymoma(epithelial) (malignant)
      • anaplastic
        • unspecified site
    • Ependymoma(epithelial) (malignant)
      • unspecified site
    • Gemistocytoma
      • unspecified site
    • Glioblastoma(multiforme)
      • with sarcomatous component
        • unspecified site
    • Glioblastoma(multiforme)
      • giant cell
        • unspecified site
    • Glioblastoma(multiforme)
      • unspecified site
    • Glioma(malignant)
      • astrocytic
        • unspecified site
    • Glioma(malignant)
      • mixed
        • unspecified site
    • Glioma(malignant)
      • unspecified site
    • Gliosarcoma
      • unspecified site
    • Oligoastrocytoma
      • unspecified site
    • Oligodendroblastoma
      • unspecified site
    • Oligodendroglioma
      • anaplastic type
        • unspecified site
    • Oligodendroglioma
      • unspecified site
    • Sarcoma(of)
      • monstrocellular
        • unspecified site
    • Spongioblastoma(any type)
      • unspecified site
    • Tumor
      • neuroectodermal (peripheral)
        • primitive
          • unspecified site
    • Xanthoastrocytoma
      • unspecified site

Clinical ClassificationClinical

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

CCSR NEO048
Nervous system cancers - brain
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Ganglioneuroblastoma

    a moderately malignant neoplasm composed of primitive neuroectodermal cells dispersed in myxomatous or fibrous stroma intermixed with mature ganglion cells. it may undergo transformation into a neuroblastoma. it arises from the sympathetic trunk or less frequently from the adrenal medulla, cerebral cortex, and other locations. cervical ganglioneuroblastomas may be associated with horner syndrome and the tumor may occasionally secrete vasoactive intestinal peptide, resulting in chronic diarrhea.

  • Medulloblastoma

    a malignant neoplasm that may be classified either as a glioma or as a primitive neuroectodermal tumor of childhood (see neuroectodermal tumor, primitive). the tumor occurs most frequently in the first decade of life with the most typical location being the cerebellar vermis. histologic features include a high degree of cellularity, frequent mitotic figures, and a tendency for the cells to organize into sheets or form rosettes. medulloblastoma have a high propensity to spread throughout the craniospinal intradural axis. (from devita et al., cancer: principles and practice of oncology, 5th ed, pp2060-1)

  • Ependymoma

    glioma derived from ependymoglial cells that tend to present as malignant intracranial tumors in children and as benign intraspinal neoplasms in adults. it may arise from any level of the ventricular system or central canal of the spinal cord. intracranial ependymomas most frequently originate in the fourth ventricle and histologically are densely cellular tumors which may contain ependymal tubules and perivascular pseudorosettes. spinal ependymomas are usually benign papillary or myxopapillary tumors. (from devita et al., principles and practice of oncology, 5th ed, p2018; escourolle et al., manual of basic neuropathology, 2nd ed, pp28-9)

  • Oligodendroglioma

    a relatively slow-growing glioma that is derived from oligodendrocytes and tends to occur in the cerebral hemispheres, thalamus, or lateral ventricle. they may present at any age, but are most frequent in the third to fifth decades, with an earlier incidence peak in the first decade. histologically, these tumors are encapsulated, relatively avascular, and tend to form cysts and microcalcifications. neoplastic cells tend to have small round nuclei surrounded by unstained nuclei. the tumors may vary from well-differentiated to highly anaplastic forms. (from devita et al., cancer: principles and practice of oncology, 5th ed, p2052; adams et al., principles of neurology, 6th ed, p655)

  • Horner Syndrome

    a syndrome associated with defective sympathetic innervation to one side of the face, including the eye. clinical features include miosis; mild blepharoptosis; and hemifacial anhidrosis (decreased sweating)(see hypohidrosis). lesions of the brain stem; cervical spinal cord; first thoracic nerve root; apex of the lung; carotid artery; cavernous sinus; and apex of the orbit may cause this condition. (from miller et al., clinical neuro-ophthalmology, 4th ed, pp500-11)

  • Suprasellar Germ Cell Tumor

    a germ cell tumor that arises from the suprasellar region.

Table of NeoplasmsClinical

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

SiteMalig.
Primary		Malig.
Secondary		Ca
in situ		BenignUncertainUnspec.
brain NECC71.9C79.31–D33.2D43.2D49.6
cranial (fossa, any)C71.9C79.31–D33.2D43.2D49.6
fossa (of)C71.9C79.31–D33.2D43.2D49.6
fossa (of) › anterior (cranial)C71.9C79.31–D33.2D43.2D49.6
fossa (of) › cranialC71.9C79.31–D33.2D43.2D49.6
fossa (of) › middle (cranial)C71.9C79.31–D33.2D43.2D49.6
fossa (of) › posterior (cranial)C71.9C79.31–D33.2D43.2D49.6
intracranial NECC71.9C79.31–D33.2D43.2D49.6
motor tract › brainC71.9C79.31–D33.2D43.2D49.6
posterior fossa (cranial)C71.9C79.31–D33.2D43.2D49.6
suprasellar (region)C71.9C79.31–D33.2D43.2D49.6

Patient EducationClinical

Brain Tumors

A brain tumor is a growth of abnormal cells in the tissues of the brain. Brain tumors can be benign, with no cancer cells, or malignant, with cancer cells that grow quickly. Some are primary brain tumors, which start in the brain. Others are metastatic, and they start somewhere else in the body and move to the brain.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert C71.9 to ICD-9-CMHistory

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

ICD-9-CM
191.9 Malig neo brain NOS
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About C71.9Overview

Is C71.9 (Malignant neoplasm of brain) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report malignant neoplasm of brain, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of C71.9?

Under the General Equivalence Mappings, malignant neoplasm of brain, unspecified converts to ICD-9-CM 191.9 (malig neo brain NOS). The mapping is a direct match.

Footnotes

[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.