BRAIN TUMOR

What is it?  Brain neoplasms are a diverse group of primary (nonmetastatic) tumors arising from one of the many different cell types within the central nervous system.  Malignant brain tumors are defined by histopathologic features and a rapidly progressive pattern of growth  Glioblastoma is the most common primary brain tumor in adults, accounting fo 50% to 60% of primary brain tumors

Pathophysiology  Nervous system tumors are clonal proliferations that develop secondary to changes in key growth regulatory genes  These genetic changes result in powerful growth advantages that enable the cells to priloferate, evolve, and disseminate  The etiologies of brain tumors remain unknown.  To date, only radiation and hereditary predisposition are clearly implicated as etiological factors  The WHO classification currently lists more than 100 types of nervous system tumors and their variants  This classification system allows for consideration of key clinical and imaging characteristics which can narrow the differential diagnosis to only a few common possibilities

Pathophysiology  Only about 5% of primary brain tumors have known hereditary factors  Li-Fraumeni syndrome, p53 defects, neurofibromatosis 1 (NF1) and 2 (NF2), tuberous sclerosis, von Hippel-Lindau disease, Turcot’s syndrome, and familial polyposis  Meningiomas  Strongest genetic link has been associated with NF2, an almost 50% incidence  Known to express estrogen and progesterone receptors.  High incidence of somatostatin receptors has also been found  Significance of these findings is uncertain but has led to diagnostic tests and treatment strategies  Radiation is only definite cause  Oligodendrogliomas  Viral infections (specifically the JC virus) has been implicated, but data are inconclusive

Incidence  Glioblastomas occur in approximately 2-3 cases/100,000 persons  Most commonly diagnosed primary brain tumor of adults is glioblastoma mulitforme (grade IV)  Slightly more common in whites than blacks, Latinos, and Asians  Slightly more common in men than women with a male:female ration of 3:2  Peak incidence is between 45 and 70 years.  Approximately 10% of glioblastomas occur in children

Risk Factors  Prior radiation may increase risk for primary brain tumor

Signs and Symptoms  Headache  Most common presenting complaint – reported by approximately 50% of the patients  Seizures (occur in 30%-60% of cases)  Signs and symptoms of hydrocephalus (headache, vomiting, clouding of consciousness, papilledema)  Memory loss  Focal motor weakness  Visual changes  Language deficits  Cognitive disturbances  Memory changes

Clinical Presentation  Worsening headache  Present for weeks to months  Classic triad of brain tumor headache: Sleep disturbances Severe pain Nausea and vomiting  Headache is often bilateral and worsened by coughing, sneezing, bending, defecation, and sexual intercourse

Imaging  MRI with and without contrast is the imaging study of choice  CT scanning is useful if calcification or hemorrhage is suspected  PET scan is helpful to distinguish neoplastic lesions (with high rate of metabolism) from other lesions such as demyelination or radiation necrosis (with a much lower metabolic rate)

Treatment  Surgery  Radiation  Palliative chemotherapy

References  Bradley W G. Neurology in Clinical Practice. 5th edition ed. Philadelphia: Butterworth Heinemann Elsevier;  Carey WD. Cleveland Clinic: Current Clinical Medicine. 2nd edition ed. Philadelphia: Saunders Elsevier;  Ferri F F. Ferri's Clinical Advisor 2011: Instant Diagnosis and Treatment. 1st ed. Philadelphia: Elsevier;  Marx J A. Rosen's Emergency Medicine. Vol 1. 7th edition ed. Philadelphia: Mosby Elsevier; 2010.