A 54-year-old physician with a history of lung cancer presents after a grand mal seizure with a several month history of increasing headaches. Which of the following statement(s) is/are true concerning this patient?

a. Lung cancer as well as breast, kidney, testicular and colon cancer are the most common primary sites to metastasize to the brain

b. A symptomatic, solitary metastatic brain lesion should be removed if surgically accessible 

d. Symptoms of cranial nerve palsies, radiculopathies and nuchal rigidity are suggestive of meningeal carcinomatosis

The percentage of intracranial tumors representing metastases approach 25%. Malignant cells invade the CNS hematogenously and tend to lodge at the grey and white matter junction. Although any malignancy has the potential to metastasize to the brain, the most common primary sites are the lung, breast, kidney, testes, colon, and skin. The presenting symptoms are determined by the site or sites of the metastases. Symptoms commonly include headache, mental status changes, seizures and hemiparesis. In general, a symptomatic solitary lesion that is surgically accessible should be removed if the patient has at least a six-month life expectancy. Surgery should not be undertaken for multiple lesions or in patients who are severely afflicted by their primary disease. Whole brain irradiation is almost always indicated after surgical resection. There is little evidence that chemotherapy plays a significant role. Tumor metastasis to the leptomeninges (meningiocarcinomatosis) is also common particularly in adults with lymphoma, breast, and lung cancer. Patients may present with cranial nerve palsies, radiculopathies, obstructive hydrocephalus. They often have signs and symptoms suggestive of meningitis. Analysis of the CSF is usually critical, often revealing increased opening pressure, elevated white blood cell count and protein levels, and a decreased glucose. Cytology should always be obtained, however it is not universally positive for malignant cells.