2026 ICD-10-CM Diagnosis Code D49.6Neoplasm of unspecified behavior of brain

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

• Basal Ganglia

  large subcortical nuclear masses derived from the telencephalon and located in the basal regions of the cerebral hemispheres.

• Basal Ganglia Cerebrovascular Disease

  a pathological condition caused by impaired blood flow in the basal regions of cerebral hemispheres (basal ganglia), such as infarction; hemorrhage; or ischemia in vessels of this brain region including the lateral lenticulostriate arteries. primary clinical manifestations include involuntary movements (dyskinesias) and muscle weakness (hemiparesis).

• Basal Ganglia Diseases

  diseases of the basal ganglia including the putamen; globus pallidus; claustrum; amygdala; and caudate nucleus. dyskinesias (most notably involuntary movements and alterations of the rate of movement) represent the primary clinical manifestations of these disorders. common etiologies include cerebrovascular disorders; neurodegenerative diseases; and craniocerebral trauma.

• Basal Ganglia Hemorrhage

  bleeding within the subcortical regions of cerebral hemispheres (basal ganglia). it is often associated with hypertension or arteriovenous malformations. clinical manifestations may include headache; dyskinesias; and hemiparesis.

• Globus Pallidus

  the representation of the phylogenetically oldest part of the corpus striatum called the paleostriatum. it forms the smaller, more medial part of the lentiform nucleus.

• Anterior Hypothalamic Nucleus

  loose heterogeneous collection of cells in the anterior hypothalamus, continuous rostrally with the medial and lateral preoptic areas and caudally with the tuber cinereum.

• Arcuate Nucleus of Hypothalamus

  a nucleus located in the middle hypothalamus in the most ventral part of the third ventricle near the entrance of the infundibular recess. its small cells are in close contact with the ependyma.

• Hypothalamic Area, Lateral

  area in the hypothalamus bounded medially by the mammillothalamic tract and the anterior column of the fornix (brain). the medial edge of the internal capsule and the subthalamic region form its lateral boundary. it contains the lateral hypothalamic nucleus, tuberomammillary nucleus, lateral tuberal nuclei, and fibers of the medial forebrain bundle.

• Hypothalamic Neoplasms

  benign and malignant tumors of the hypothalamus. pilocytic astrocytomas and hamartomas are relatively frequent histologic types. neoplasms of the hypothalamus frequently originate from adjacent structures, including the optic chiasm, optic nerve (see optic nerve neoplasms), and pituitary gland (see pituitary neoplasms). relatively frequent clinical manifestations include visual loss, developmental delay, macrocephaly, and precocious puberty. (from devita et al., cancer: principles and practice of oncology, 5th ed, p2051)

• Hypothalamus

  ventral part of the diencephalon extending from the region of the optic chiasm to the caudal border of the mammillary bodies and forming the inferior and lateral walls of the third ventricle.

• Hypothalamus, Anterior

  the front portion of the hypothalamus separated into the preoptic region and the supraoptic region. the preoptic region is made up of the periventricular gray matter of the rostral portion of the third ventricle and contains the preoptic ventricular nucleus and the medial preoptic nucleus. the supraoptic region contains the paraventricular hypothalamic nucleus, the supraoptic nucleus, the anterior hypothalamic nucleus, and the suprachiasmatic nucleus.

• Hypothalamus, Middle

  middle portion of the hypothalamus containing the arcuate, dorsomedial, ventromedial nuclei, the tuber cinereum and the pituitary gland.

• Hypothalamus, Posterior

  the part of the hypothalamus posterior to the middle region consisting of several nuclei including the medial maxillary nucleus, lateral mammillary nucleus, and posterior hypothalamic nucleus (posterior hypothalamic area). the posterior hypothalamic area is concerned with control of sympathetic responses and is sensitive to conditions of decreasing temperature and controls the mechanisms for the conservation and increased production of heat.

• Pituitary Gland

  a small, unpaired gland situated in the sella turcica. it is connected to the hypothalamus by a short stalk which is called the infundibulum.

• Supraoptic Nucleus

  hypothalamic nucleus overlying the beginning of the optic tract.

• Putamen

  the largest and most lateral of the basal ganglia lying between the lateral medullary lamina of the globus pallidus and the external capsule. it is part of the neostriatum and forms part of the lentiform nucleus along with the globus pallidus.

• Putaminal Hemorrhage

  intracranial bleeding into the putamen, a basal ganglia nucleus. this is associated with hypertension and lipohyalinosis of small blood vessels in the putamen. clinical manifestations vary with the size of hemorrhage, but include hemiparesis; headache; and alterations of consciousness.

• Anterior Thalamic Nuclei

  three nuclei located beneath the dorsal surface of the most rostral part of the thalamus. the group includes the anterodorsal nucleus, anteromedial nucleus, and anteroventral nucleus. all receive connections from the mamillary body and brain fornix, and project fibers to the cingulate body.

• Intralaminar Thalamic Nuclei

  cell groups within the internal medullary lamina of the thalamus. they include a rostral division comprising the paracentral, central lateral, central dorsal, and central medial nuclei, and a caudal division composed of the centromedian and parafascicular nuclei.

• Mediodorsal Thalamic Nucleus

  the largest of the medial nuclei of the thalamus. it makes extensive connections with most of the other thalamic nuclei.

• Midline Thalamic Nuclei

  small, nonspecific nerve cells scattered in the periventricular gray matter, separating the medial part of the thalamus from the ependyma of the third ventricle. the group includes the paraventricular nucleus, paratenial nucleus, reuniens nucleus, rhomboidal nucleus, and subfascular nucleus.

• Posterior Thalamic Nuclei

  a transitional diencephalic zone of the thalamus consisting of complex and varied cells lying caudal to the ventral posterolateral nucleus, medial to the rostral part of the pulvinar, and dorsal to the medial geniculate body. it contains the limitans, posterior, suprageniculate, and submedial nuclei.

• Pulvinar

  large mass of nuclei forming the most caudal portion of the thalamus and overhanging the geniculate bodies and the dorsolateral surface of the midbrain. it is divided into four parts: the lateral, medial, inferior, and oral pulvinar nuclei.

• Thalamus

  paired bodies containing mostly gray matter and forming part of the lateral wall of the third ventricle of the brain.

• Ventral Thalamic Nuclei

  a large group of nuclei lying between the internal medullary lamina and the internal capsule. it includes the ventral anterior, ventral lateral, and ventral posterior nuclei.

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

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Brain Diseases

Your brain is the control center of your body. It controls your thoughts, memory, speech, and movement. It regulates the function of many organs. It's part of your nervous system, which also includes your spinal cord and peripheral nerves. The nervous system sends signals between your brain and the rest of the body.

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