A brain tumor is an abnormal growth occurring in any tissue contained within the cranium, including the brain, cranial nerves, meninges, skull, pituitary gland, and pineal gland. Tumors may be benign or malignant and originate from within the cranium (primary tumors) or from a metastatic tumor found elsewhere (secondary tumors). Many variants have been identified and classified according to 2016 WHO criteria.   Patients commonly present with signs of intracranial pressure (e.g., headache, altered mental status, nausea, and/or vomiting) and gait abnormality.
Primary tumor of the cranial and spinal compartments. Estimates indicate that meningioma represent over 36% of primary brain tumors and 53.5% of all nonmalignant tumors.  They are more common in women, and are usually benign. Neurologic deficit and progressive, focal, or general headaches (in large tumors) are common. Tumors may also produce visible bony growth. Diagnosis is confirmed by the characteristic appearance on magnetic resonance imaging (MRI), with and without contrast enhancement. Asymptomatic lesions may be followed up with serial observation.  Treatment of symptomatic meningioma is usually surgical resection,  although, in some cases, local radiation therapy is used as primary treatment. 
Benign, slow-growing cerebellopontine angle tumor that grows from the superior vestibular component of the vestibulocochlear nerve. Usually presents with unilateral sensorineural hearing loss,   but may be found on routine hearing examinations. Progressive dizziness and unilateral facial numbness are also common. Neurofibromatosis type 2, a rare autosomal dominant disorder, is a strong risk factor. Diagnosis is confirmed by gadolinium-enhanced MRI. Observation may be appropriate management,  with stereotactic radiation or radiosurgery or formal surgical resection as definitive treatment options.  
Malignant, invasive brain tumor arising from the cerebellar vermis. The vast majority of medulloblastomas arise sporadically in the first 2 decades of life, and they are one of the most common brain tumors of childhood.  Symptoms, as a result of a mass effect from the tumor or due to obstructive hydrocephalus, include morning headaches, nausea, vomiting, diplopia (a manifestation of sixth nerve palsy), and ataxia. Vomiting often relieves the headaches. Cranial CT and MRI are essential diagnostic and postoperative investigations. Primary treatment is surgical resection with postoperative chemotherapy and irradiation, depending on risk stratification. 
Primary tumor of the brain arising from astrocytes, which are an important part of the blood-brain barrier. A neuroepithelial type tumor categorized by histologic type and grade with each subtype having a different age-adjusted incidence rate, behavior, and clinical course.  Patients may present with focal neurologic deficits according to location (e.g., frontal, temporal, cerebellum, brainstem) or with signs of elevated intracranial pressure. It is more common in industrial countries and in white males.   Diagnosis is by cranial imaging with surgical biopsy. Treatment depends on tumor grade and may include surgery, radiotherapy, and chemotherapy. Prognosis can range from good for low-grade benign to poor for high-grade astrocytomas.
Benign extra-axial nonglial epithelial tumor of the CNS, seen in both children and adults. Craniopharyngiomas most commonly arise within the sellar/suprasellar space. Although it may present at any age, a bimodal age distribution is reported with a peak between 5 and 14 years in children and between 50 and 70 years in adults.    Craniopharyngiomas will cause mass effect symptoms, including visual loss or symptoms of intracranial hypertension.  Pituitary dysfunction is also common; children may present with growth failure and adults with diabetes insipidus and sexual dysfunction.  Diagnostic evaluation includes cranial CT/MRI and full endocrine evaluation. Primary treatment is surgical resection, with postoperative radiotherapy in select cases.  
An uncommon tumor, accounting for <1% of all non-Hodgkin lymphoma. Risk factors include immunosuppression, especially HIV infection, where an association with EBV infection is recognized.  Diagnosis is based on cranial CT and clinical history, with LP and CSF analysis. The most effective treatment is methotrexate-based chemotherapy with adjunctive whole-brain radiation therapy.  Adding cytarabine to methotrexate is a standard approach in some centers. 
Clinically nonfunctional adenomas (CNFA) are associated with multiple endocrine neoplasia type 1 (MEN-1),  familial isolated pituitary adenomas,  and Carney complex.  May present with features of hormonal insufficiency. Most symptoms are longstanding and progress slowly. Diagnosis is via endocrine evaluation and cranial imaging. Treatment strategies include observation with serial imaging, surgical resection, and radiotherapy. 
Acromegaly is due to a pituitary somatotroph adenoma in about 99% of cases. Pituitary somatotroph adenomas chronically secrete excessive GH, which stimulates insulin-like growth factor-1 (IGF-1) production, leading to the majority of the clinical manifestations of the acromegaly.  Diagnosis is based on biochemical confirmation of IGF-1 hypersecretion. Treatment includes surgical resection and/or somatostatin analogs.  
Cushing disease, which is hypercortisolism caused by an ACTH-secreting pituitary adenoma, is the most common cause of Cushing syndrome and is responsible for the majority of cases. Diagnosis is by demonstration of unsuppressed ACTH and subsequent cranial MRI. First-line therapy is generally transsphenoidal surgical resection.
Benign prolactin-expressing and secreting pituitary adenoma. It is more frequent in women, mainly during the childbearing years.  Prolactinoma leads to hyperprolactinemia, which results in hypogonadism, sexual dysfunction, and galactorrhea, and it may also cause hypopituitarism and osteoporosis. There may be symptoms of mass effect.  Assessment of serum prolactin levels with cranial imaging are standard diagnostic tests.  Medical treatment with dopamine agonists is the primary treatment for both sexes, with surgery reserved for refractory cases.  
Pituitary adenomas may be divided into 2 types: clinically nonfunctional adenoma (CNFA), where there is no hypersecretion of hormone, and functional adenoma, where there is hypersecretion of hormone. Functional adenomas are found in acromegaly, Cushing disease, and prolactinoma. Compression of adjacent structures may cause mass effect symptoms (visual disturbances, ophthalmoplegia, headaches).
The majority of patients presenting with acute headache have a benign diagnosis, but a high index of suspicion should be maintained for life-threatening causes of headache.  Most brain tumors causing headaches can be seen on nonenhancing contrast CT.
Headaches are common in children, increasing in incidence from early childhood to adolescence. They account for 0.7% to 1.3% of all pediatric ER visits.   Of children with brain tumors, 62% have headache prior to diagnosis, and 98% have at least one neurologic symptom or abnormality on examination. 
Ataxia can be hereditary or acquired. It can be cerebellar, sensory, or vestibular in origin. The list of acquired causes is extensive and includes vascular, demyelinating, neoplastic, autoimmune, toxic, degenerative, compressive, and infectious etiologies.
Hyperprolactinemia may be caused by prolactinomas (micro- or macroadenomas), acromegaly, or interruption of the hypothalamic-pituitary axis.
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This overview has been compiled using the information in existing sub-topics.
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