The patient’s left-sided weakness improved significantly with steroids. CT of the chest, abdomen, and pelvis was unremarkable. The bone scan failed to reveal evidence of skeletal lesions. Surgical intervention was sought to establish a histologic diagnosis and alleviate mass effect for symptom relief and improvement in quality of life.

• A 4 × 4-cm right parietal lobe mass with significant vasogenic edema
  
• This lesion exerts mass effect on the right lateral ventricle and right to left midline shift of 7 mm.

• There is a solitary 4.4 × 4-cm ring-enhancing lesion in the right posterior parietal region near the postcentral sulcus.
  
• There is a significant amount of vasogenic edema subcortically, throughout the right centrum semiovale.

• Primary brain tumor (astrocytoma/glioblastoma multiforme)
  
• Metastasis
  
• Cerebral abscess
  
• Other: resolving hematoma, lymphoma, infarction, and demyelination

• Admission to the intensive care unit for close neurologic observation
  
• Because the patient is highly symptomatic from significant cerebral edema, the patient should be given steroids immediately: dexamethasone 10 mg intravenous (i.v.) bolus followed by 6 mg i.v. every 6 hours with gastrointestinal prophylaxis.
  
• Consideration should be given to the use of prophylactic antiepileptic drugs, although controversial because the patient has not had a seizure.
  
• Expeditiously, a metastatic workup can be performed, consisting of a CT scan of the chest, abdomen, and pelvis; a radiograph of the chest; a bone scan; stool guaiac test; and tests using appropriate laboratory tumor markers.

• Lung, breast, renal cell, colon cancer, and melanoma.¹ Lung, colon, and renal cancers account for 80% of metastatic brain tumors in men.
  
• However, breast, lung, colon, and melanoma cancers account for 80% of metastatic brain tumors in women.

• Surgical intervention is necessary to obtain a histologic diagnosis and alleviate mass effect. Differentiating between neoplastic and infectious etiology is critical. If neoplastic, the tissue type has significant prognostic value and treatment implications.
  
• Metastatic tumors typically require adjuvant postoperative WBRT.
  
• However, if the lesion is of infectious etiology, the treatment options are radically different (i.e., i.v. antibiotics).

• In a randomized trial of surgery in the treatment of single metastases to the brain,² patients were randomly assigned to surgical removal of the brain tumor followed by RT (surgical group) or needle biopsy and RT (radiation group).
  
• The overall length of survival was significantly longer in the surgical group (median, 40 weeks versus 15 weeks in the radiation group; P <0.01).
  
• Patients treated with surgery remained functionally independent longer (median, 38 weeks versus 8 weeks in the radiation group; P <0.005).
  
• This study demonstrated increases survival with a lower recurrence rate in those individuals with surgical resection of their single metastasis.

• Advantages of SRS
  
  
  
  • Noninvasive, general anesthesia is avoided.
    
  • Radiation doses to normal brain tissue are minimized.
    
  • Treatable lesions include those that are surgically inaccessible.
    
  • SRS can sometimes be effective for typically radioresistant tumors such as melanoma, renal cell carcinoma, and sarcoma.3
    
  • The addition of SRS to WBRT may improve neurologic outcomes in selected patients who are candidates for SRS.^4,5
  
  
• Disadvantages of SRS include a treatment restriction to lesions under 4 cm. Also symptomatic radionecrosis may occur, which at times requires treatment with steroids or surgical resection.⁶

• Patchell et al.⁷ randomly assigned patients to treatment with postoperative WBRT or no further treatment after complete surgical resections for their brain metastasis.
  
• Tumor recurrence was less frequent in the RT group than in the observation group (18 vs. 70%).
  
• Postoperative RT prevented local recurrence (10 vs. 46%).
  
• Patients in the RT group were less likely to die of neurologic causes than were patients in the observation group (14% of whom died vs. 44%).

• Initial and second reoperation was shown to improve survival and quality of life in patients with recurrent disease.⁸
  
• Factors shown to negatively influence survival
  
  
  
  • Presence of systemic disease
    
  • Lower Karnofsky performance score (KPS; <70)
    
  • Short time to recurrence (<4 months), age (>40)
    
  • Specific types of primary tumor (breast or melanoma)⁸

• Preoperatively, functional MRI (fMRI) can be matched with high-resolution MR or CT navigation to aid in delineating eloquent areas in the brain.⁹
  
• Intraoperatively, cortical mapping is most commonly used when resecting lesions near the sensorimotor cortex.
  
• Direct bipolar electrical stimulation of exposed cortex for motor cortex mapping is favored over monitoring of cortical somatosensory evoked potentials and phase reversal phenomena.¹⁰
  
• Furthermore, an awake craniotomy technique is used for lesions in or around the speech center.

• Long-term complications include radiation-induced neurotoxicity, symptoms of which include dementia, gait ataxia, and incontinence.¹¹
  
• Elderly patients are at particular risk for this complication.
  
• Symptomatic radionecrosis may also occur, which at times requires treatment with steroids or surgical resection.

• Emerging technology includes Iodine-125 brachytherapy. Dagnew et al.⁶ researched placement of permanent brachytherapy with ¹²⁵I seeds, after the gross total resection of single brain metastasis.
  
• At median follow-up evaluation of 12 months, the local tumor control rate was 96%. Median survival was 17.8 months.
  
• The author states that 92% never required WBRT, avoiding potential radiation-induced neurotoxicity.⁶
  
• Results of the Phase II GliaSite Trial revealed local tumor control rate and survival to be similar to individuals who underwent surgical resection of a single metastasis + WBRT¹² (implantable inflatable balloon catheter and liquid ¹²⁵I radiation source.¹²)

• In a retrospective study of 342 patients, survival was not statistically different between patients with an undiagnosed primary lesion versus those with a diagnosed primary tumor.¹³
  
• The authors conclude that delaying treatment in pursuit of a primary diagnosis may not be appropriate.¹³