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?

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.