This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CNS Tumors, Subject name: Surgery
[{'content': 'A 60-year-old otherwise healthy woman Presents to her physician with a 3-week history of severe headaches. A contrast CT scan reveals a small, circular, hypodense lesion with ring like contrast enhancement. Which of the following is the most likely diagnosis? \nSelect and explain. \nA. High-grade astrocytoma, B. Metastatic lesion, C. Parenchymal Haemorrhage, D. Brain abscess', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Although these CT findings can be consistent with all the options given but in immunocompetent individual there is more incidence of it being a metastatic lesion. M/C cancers to metastasise to brain includes :- Lung CA, Breast CA, Melanomas, RCC, few GI tumours. These lesions become symptomatic due to mass effect from white matter edema. Rx- includes combination of Sx, radios, and whole brain radiation therapy. Immunocompromised patients are at increased risk for toxoplasmosis and central nervous system lymphomas.', 'role': 'assistant'}]