Brain Tumor
Brain Tumor: Excerpt from The 5-Minute Pediatric Consult
Michael J. Fisher, MD
Brain Tumor - BASICS
Brain Tumor - description
A primary neoplasm arising in the CNS
Brain Tumor - epidemiology
Brain Tumor - incidence
- Most common solid neoplasm of childhood (2nd to leukemia in overall incidence)
- Incidence rising (>3,000 new cases/year)
- 3.9 cases/100,000 children/year
- Peak incidence in children ≤7 years of age
Brain Tumor - prevalence
- Slight male predominance
- Majority arise infratentorially (within cerebellum or brainstem) in children 1–11 years of age
- Majority arise supratentorially in children <1 year of age
Brain Tumor - risk factors
Brain Tumor - genetics
- Not a heritable condition
- Primary CNS tumors are associated with several familial syndromes:
- Neurofibromatosis with optic pathway gliomas (NF1) and meningiomas (NF2)
- Tuberous sclerosis with gliomas and rarely ependymomas
- Li-Fraumeni syndrome with astrocytomas
- Von Hippel-Lindau with cerebellar hemangioblastoma
- Turcot syndrome with primitive neuroectodermal tumor
Brain Tumor - pathophysiology
The majority of tumors are classified based on their histology. The most common:
- Glioma:
- Arises from astrocytes (supportive tissue)
- >50% of childhood CNS tumors
- Ranges from low grade (often in the cerebellum or optic pathway) to high grade (grade III to IV; in the cerebrum or brainstem)
- Locally recurrent and invasive when high grade
- Primitive neuroectodermal tumor/medulloblastoma:
- Malignant embryonal tumor arising from unknown cell type
- Comprises ~20% of childhood CNS tumors
- Most common malignant brain tumor in children
- Majority arise in the midline of the cerebellum (referred to as medulloblastoma)
- Predisposition for leptomeningeal dissemination
- Ependymoma:
- Arises from ependymal cells that line the ventricular system
- 8–10% of childhood CNS tumors
- Most commonly occurs in the 4th ventricle; may arise in the spinal cord
- Locally recurrent and invasive; spinal metastases rare at initial diagnosis
- Germ cell tumor:
- Derived from totipotent germ cells
- 3–5% of childhood CNS tumors
- Majority are located in the pineal or suprasellar region
- Atypical teratoid/rhabdoid tumor:
- Rare embryonal tumor arising from unknown cell type; often misdiagnosed as primitive neuroectodermal tumor
- <3% of childhood CNS tumors
- Majority arise in children <5 years of age
- Propensity to arise in the posterior fossa with frequent leptomeningeal dissemination; reported in association with malignant rhabdoid tumors of the kidney
- Craniopharyngioma: 6–9% of childhood CNS tumors
- Tumors of the choroid plexus
- Ganglioglioma
- Meningioma and hemangioblastoma, rare in children
Brain Tumor - etiology
No specific causative agents are known, but there is an association with radiation, chemical exposure, other malignancies, familial/heritable diseases, immunosuppression (lymphoma)
Brain Tumor - DIAGNOSIS
Brain Tumor - signs & symptoms
Tumor location dictates symptoms and signs.
Brain Tumor - history
- Headache and vomiting (particularly in the morning), irritability and lethargy are associated with increased intracranial pressure
- Difficulty swallowing, slurred speech, and diplopia may indicate brainstem tumor.
- Visual field deficits (bumps into things) could indicate optic tract lesion.
- Focal weakness hints at pyramidal tract lesion.
- Ataxia may be a sign of cerebellar lesion.
- Changes in behavior or school performance, new-onset seizures, and weakness could be signs of supratentorial lesion.
- Polyuria/polydipsia may indicate hypothalamic/pituitary lesion.
- Failure to thrive, emaciation, euphoria, and increased appetite in an infant may indicate hypothalamic lesion (diencephalic syndrome).
- Back pain, extremity weakness, bowel/bladder dysfunction could signify spinal cord metastases (often seen with primitive neuroectodermal tumor/medulloblastoma and germ cell tumors)
Brain Tumor - physical exam
- Macrocephaly, bulging fontanelle, papilledema, impaired upgaze are signs of increased intracranial pressure.
- Focal deficit on neurologic examination helps localize the mass lesion:
- Isolated cranial nerve VI and VII palsies may indicate brainstem tumor.
- Ataxia, dysmetria could indicate cerebellar mass.
- Decreased visual acuity, visual field deficit, absent pupillary light response, strabismus may all be signs of optic tract tumor.
- Changes in cognitive function, mood, and affect could indicate supratentorial lesion.
- Impaired upgaze, convergence nystagmus, pupils respond to accommodation but poorly to light are signs of pineal lesion (Parinaud syndrome).
- Signs of neurocutaneous disease (e.g., café-au-lait spots, Lisch nodules) may indicate a syndrome such as neurofibromatosis.
Brain Tumor - tests
Brain Tumor - imaging
- MRI with and without gadolinium enhancement is the “gold standard” for identification, localization, and characterization of tumors.
- CT can be used as an initial study, but if negative and a high index of suspicion, follow with MRI. Useful to evaluate for hydrocephalus and hemorrhage.
Brain Tumor - diag proced-surgery
Staging of tumor:
- Postoperative head MRI within 24–48 hours to determine residual disease before postoperative inflammatory changes are prominent
- Spine MRI and CSF cytology required for neuraxis staging of tumors with high risk of leptomeningeal dissemination
- Elevated α-fetoprotein and quantitative β-human chorionic gonadotropin CSF and serum are markers for germ cell tumors.
Brain Tumor - differencial diagnosis
- Infection: Cerebral abscess
- Tumors: Metastatic tumor to brain, uncommon with childhood solid tumors
- Trauma: Hemorrhage unlikely to be confused with tumor
- Congenital:
- Arteriovenous malformation
- Hamartoma
- Dysplastic brain
- Psychosocial: Some patients with nausea, vomiting, or behavior changes are first diagnosed with psychiatric disorders, gastrointestinal disorders, failure to thrive, or anorexia nervosa prior to discovery of a brain tumor.
New onset of psychoses should prompt imaging to rule out tumor.
Brain Tumor - TREATMENT
Brain Tumor - surgery
- Both for histology and to attempt maximal tumor debulking; should be performed by experienced pediatric neurosurgeon
- Rarely indicated in intrinsic pontine (brainstem) glioma
- Ventriculoperitoneal shunt when needed for obstructive hydrocephalus (risk of peritoneal seeding minimal)
Patient should be referred to a pediatric brain tumor/oncology center at diagnosis (preoperatively).
Brain Tumor - radiotherapy
- Volume and dose vary depending on histology.
- Radiation therapy to the tumor bed is used for most patients with brain tumors.
- Medulloblastoma/primitive neuroectodermal tumor patients need craniospinal radiation therapy. The one exception is infants and young children (<3 years of age), in whom cognitive deficits from radiation therapy can be devastating.
- Duration of radiation therapy: 6 weeks
Brain Tumor - medication
- Dexamethasone to control increased intracranial pressure (0.5 mg/kg divided q6h)
- Chemotherapy:
- Drugs are most often used in combination:
- Carboplatin, vincristine, or 6-thioguanine, procarbazine, CCNU, vincristine for low-grade glioma
- Cisplatin, CCNU, vincristine, etoposide, cyclophosphamide are active agents for primitive neuroectodermal tumor/medulloblastoma
- Temozolomide for high-grade glioma
- New protocols currently being evaluated:
- High-dose chemotherapy with stem cell rescue for high-risk primitive neuroectodermal tumor/medulloblastoma
- Targeted therapies, angiogenesis inhibitors
- Duration of chemotherapy: 6 months to 2 years
Possible conflict with other treatments: Chemotherapy can alter anticonvulsant levels.
Brain Tumor - FOLLOW UP
- Neurologic deficits can take months to improve or stabilize with permanent deficit.
- Any worsening or relapse of symptoms must be evaluated for tumor recurrence.
- MRI every 3 months the 1st year, every 6 months for the next 2 years, and annually thereafter. Benefit of routine surveillance imaging is controversial.
Brain Tumor - prognosis
- Dependent on histology of tumor, location, and extent of initial resection.
- Glioma:
- Low grade: 70–90% 5-year event free survival
- High grade: Median survival 8–31 months; depends on grade and extent of resection
- Intrinsic pontine: Median overall survival of 9–13 months from diagnosis
- Medulloblastoma:
- 80–85% survival at 5 years if localized, gross total resection achieved, and >3 years old at diagnosis
- 30–40% survival if disseminated
- Ependymoma:
- 50–70% survival at 5 years with total resection
- <30% survival with subtotal resection
- Infants overall have a worse prognosis, possibly due to the limitations of therapy and/or the aggressiveness of the tumor.
Even benign tumors may be life threatening if their location precludes resection.
Brain Tumor - complications
- Secondary to disease:
- Increased intracranial pressure:
- Obstruction of CSF flow
- Requires immediate neurosurgical evaluation
- Secondary to radiotherapy:
- Neurocognitive sequelae (age and dose related)
- Endocrinopathy (growth hormone deficiency, hypothyroidism, gonadal dysfunction)
- Risk of second malignancies (meningioma, glioma, sarcoma)
- Secondary to chemotherapy:
- Risks associated with bone marrow suppression (infection, bleeding, anemia)
- Hearing loss
- Risk of secondary leukemia
Brain Tumor - bibliography
- Packer RJ. Brain tumors in children. Arch Neurol. 1999;56:421–425.
Phillips PC, Grotzer MA. Brain tumors in children. In: Asbury AK, McKhann GM, McDonald WI, et al., eds. Diseases of the Nervous System: Clinical Neuroscience and Therapeutic Principles. 3rd ed. Cambridge, UK: Cambridge University Press; 2002:1448–1461.Primary brain tumors in the United States: Statistical report 1995–1999. Central Brain Tumor Registry of the United States, 2002–2003.Strother DR, Pollack IF, Fisher PG, et al. Tumors of the central nervous system. In: Pizzo PA, Poplack DG, eds. Principles and Practice of Pediatric Oncology. 4th ed. Philadelphia: Lippincott Williams & Wilkins; 2002:751–824.- Valentino TL, Conway EE, Jr, Shiminski Maher T, et al. Pediatric brain tumors. Pediatr Ann. 1997;26:579–587.
Brain Tumor - CODES
Brain Tumor - icd9
191.9 Malignant neoplasm of brain, unspecified
Brain Tumor - FAQ
- Q: Are my other children at risk for getting a brain tumor?
- A: No (except in rare cases of certain familial syndromes).
- Q: Did something I do cause this?
- A: No. In addition, the claims made about high-power lines and cellular phones causing brain tumors or cancer are unproven.
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Book Source Details
- Book Title: The 5-Minute Pediatric Consult
- Author(s): M. William Schwartz MD; et al.
- Year of Publication: 2008
- Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.
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Medical Books Excerpts
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- Papilledema
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- Hypertension
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: The 5-Minute Pediatric Consult
Authors: M. William Schwartz MD; et al.
Publisher: Lippincott Williams & Wilkins
Copyright: 2008
ISBN: 0-7817-7577-9
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