Embryonal (Primitive) Neuroepithelial Tumors

Medulloblastoma Definition Malignant, embryonal tumor arising primarily in the posterior fossa of children Clinical Features Epidemiology Most common primitive neuroepithelial tumor (PNET) in CNS; 0.5 per 100,000 Peak incidence: 5 to 10 years; adults cluster in 30s 20% of brain tumors in children Most common malignant brain tumor of childhood Several familial/hereditary disorders associated with medulloblastomas Presentation Symptoms are mainly due to increased intracranial pressure, morning…

Neuronal and Glioneuronal Tumors

Ganglion Cell Tumors Definition Well – differentiated tumors of the CNS with mature neurons (ganglion cells) as a defining feature: includes ganglioglioma (ganglion cell tumor with a low-grade glial element), gangliocytoma (without a glial element), and anaplastic ganglioglioma (ganglion cells and anaplastic glial elements) Clinical Features Epidemiology 4% of primary brain tumors, ~0.2/100,000/year Most common in temporal lobe, but may arise throughout neuraxis More common in…

Choroid Plexus Tumors

Choroid Plexus Papilloma Definition Intraventricular papillary neoplasm; most common in children World Health Organization (WHO) Grade I Clinical Features Epidemiology Comprise 0.3% to 0.6% of brain tumors; 2% to 4% of pediatric brain tumors Most common in children under the age of 15 Account for 10% to 20% manifesting before the first year of life Lateral ventricular tumors arise in younger patients (<20 years) Fourth ventricle…

Tumors with Ependymal-Like Features

Angiocentric Glioma Definition Low-grade glial neoplasm (WHO Grade I) arising in childhood and typically associated with epilepsy; key pathologic features include angiocentric growth and monomorphous spindle cells; also called monomorphous angiocentric glioma and angiocentric neuroepithelial tumor Clinical Features Epidemiology Rare neoplasm arising in children and young adults (mean age 17 years) No gender predilection Typical locations: superficial cortical regions of the frontoparietal lobe and the temporal…

Ependymomas and Subependymoma

Ependymoma Definition A slowly growing tumor generally arising in the central region of the spinal cord in adults or a ventricle in children and adults Most correspond to World Health Organization (WHO) Grade II; anaplastic ependymomas are WHO Grade III Clinical Features Epidemiology Comprise 5% to 7% of all CNS tumors; no gender predilection Bimodal age distribution with first peak in childhood (2 to 16 years)…

Other Astrocytic Tumors

Pleomorphic Xanthoastrocytoma (PXA) Definition A superficially located astrocytic neoplasm usually arising in children and young adults; circumscribed tumor with reticulin deposition, significant pleomorphism, and favorable prognosis Most correspond to World Health Organization (WHO) Grade II; anaplastic PXAs are WHO Grade III Clinical Features Epidemiology Rare, accounting for less than 1% of all CNS neoplasms Typically seen in children and teenagers, with over two thirds of tumors…

Diffuse Gliomas: O ligodendroglial

Oligodendroglioma Definition A diffuse infiltrating glioma of adults consisting of cells resembling oligodendroglia, often with chromosomal deletions of 1p and 19q; typically located in the cerebral hemispheres World Health Organization (WHO) Grade II Clinical Features Epidemiology Constitute 3% of primary brain tumors and account for about 10% of all gliomas Peak incidence in fourth and fifth decades of life; children not usually affected Men slightly more…

Diffuse Gliomas: A strocytic

Diffuse Astrocytoma Definition Infiltrating glial neoplasm with astrocytic features, typically with some degree of pleomorphism, increased cellularity and slow growth; also known as low-grade diffuse astrocytoma World Health Organization (WHO) Grade II Clinical Features Epidemiology Peak incidence in fourth decade, with wide age range Slight male predominance (1.18 to 1) Accounts for 10% to 15% of all astrocytic tumors and about 5% of all primary intracranial…

Traumatic Intracranial Hemorrhage

Epidural Hematoma Definition Collection of blood within a potential space between skull and dura mater. Clinical Features Epidemiology Occurs in 1% to 4% of imaged head trauma patients Seen in 5% to 15% of patients with fatal head injuries Age range 20 to 40 years Male predilection Etiology: Head trauma with skull fracture: >90% of epidural hematomas are due to skull fracture traversing arterial groove of…

Closed Versus Open (Penetrating) Head Trauma

Contusion/Laceration (Including Coup and Contrecoup Lesions) Definition Direct injury to surface of brain parenchyma, usually involving the cortical gray matter Contusion: a “bruise” of the brain with intact pia mater Laceration: tearing of brain tissue with breached pia mater Clinical Features Epidemiology Traumatic brain injury caused 6.5% of deaths in the United States Frequency is approximately 32 per 100,000 persons Twice as frequent in children than…

Inherited Cerebrovascular Diseases

Cerebral Amyloid Angiopathy Definition Vasculopathy arising from deposition of Aβ-amyloid peptide within walls of meningeal and superficial cortical blood vessels, which can lead to acute focal, multifocal, or lobar hemorrhages; a small subset of patients develop an intense inflammatory response called Aβ-related angiitis (ABRA) Clinical Features Epidemiology Not a distinct disease, except in rare genetic forms Found in 98% of confirmed cases of Alzheimer's disease Usual…

Vasculitis

Giant Cell Arteritis Definition Panarteritis affecting medium-sized and large extracranial branches of the aorta; most common primary vasculitis to affect the nervous system Clinical Features Epidemiology Incidence: 15 to 25 cases per 100,000 Peak incidence in individuals 75 to 85 years of age Twice as common in women Presentation Classic symptoms: blindness, headache, scalp tenderness, and jaw claudication Involvement of the vertebral arteries associated with vertigo,…

Vascular Malformations

Arteriovenous Malformations (AVM) Definition Abnormal collection of thick-walled blood vessels with intervening gliotic brain tissue; arterial blood flows directly into draining veins without interposed capillary beds in this “high-flow” vascular malformation Clinical Features Epidemiology AVMs are congenital lesions Prevalence is roughly 0.15% with a slight male predominance Mean age at diagnosis is 33 years AVMs may occur in Osler-Weber-Rendu syndrome, Wyburn-Mason syndrome, and craniofacial arteriovenous metameric…

Intracranial Aneurysms

Saccular (“Berry”) Aneurysms Definition A localized dilatation or ballooning of a cerebral artery that lacks an internal elastic lamina and has disrupted muscular layers; subarachnoid hemorrhage (SAH) commonly occurs with aneurysm rupture; intraventricular hemorrhage may also occur; synonyms: saccular aneurysm, berry aneurysm, true aneurysm Clinical Features Epidemiology Prevalence is estimated at 0.2% to 5%; slight predominance among females 80% to 90% arise in anterior carotid circulation,…

Cerebral Ischemia and Hypertensive Changes

Ischemic Cerebrovascular Disease Definition Atherothrombosis of large vessels or embolic occlusion of distal vessels, resulting in absence of blood flow Majority of infarcts result from the disruption and embolization of platelet thrombi or atherosclerotic plaque material, leading to obstruction of intracranial arteries Clinical Features Epidemiology Increased risk of disease with diabetes, hypertension, smoking, family history, and hyperlipidemia Accounts for 70% to 80% of all “strokes” More…

Acquired Developmental Defects

Germinal Matrix Hemorrhage Definition Bleeding into the subependymal germinal matrix zone with or without subsequent dissection into the lateral ventricle (intraventricular hemorrhage) Germinal matrix zone (GMZ): Fetal periventricular structure that forms between the developing deep cerebral nuclei and ependymal lining Present between 13 and 36 weeks of gestation Composed of immature neuroepithelial cells and thin-walled blood vessels with little supportive stroma Clinical Findings Epidemiology Prematurity is…

Malformations

Neural Tube Defects Definition Failure in the proper closure of part or all of the neural tube; called induction disorder (neural tube induced by the notochord and paraxial mesoderm during the third to fourth week of gestation) Clinical Features Epidemiology Incidence 0.5 to 1.3 cases per 1000 live births Male-to-female ratio—about 1 : 5 Cause of neural tube defects (NTDs): multifactorial (genetic, environmental, and nutritional) Known environmental factors:…

Herniations

Definition Displacement of brain tissue from one intracranial compartment to another; these compartments are separated by rigid structures such as dura or bone Clinical Features You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If you are a member. Log in here

Hydrocephalus

Definition Buildup of cerebrospinal fluid (CSF) within the ventricles leading to brain swelling, increased intracranial pressure, and damage to brain tissue; most often caused by obstruction of CSF flow at common sites of obstruction: foramina of Monro, Luschka, and Magendie; and the aqueduct of Sylvius Examples of congenital causes include aqueductal stenosis, atresia, agenesis; Arnold-Chiari malformation, Dandy-Walker malformation, and neural tube defects, whereas examples of acquired…

Cerebral Edema

Definition Excess fluid accumulation within the brain parenchyma Brain, blood, and cerebrospinal fluid (CSF) exist in rigid compartments of skull and dura, leaving limited room for parenchymal expansion Cerebral edema results in increased intracranial pressure (ICP) Two principal types of cerebral edema: vasogenic and cytotoxic Clinical Features You’re Reading a Preview Become a Clinical Tree membership for Full access and enjoy Unlimited articles Become membership If…