A 38-year-old man from Delhi presents with a 3-month history of progressive headaches, morning vomiting, and recent-onset focal seizures. MRI brain shows a 4 cm heterogeneous mass in the left frontal lobe with surrounding edema and mass effect on the lateral ventricle. The lesion is hyperintense on T2/FLAIR, shows patchy enhancement on contrast, and has areas of necrosis. No hemorrhage is noted. Histopathology is pending. What is the most appropriate immediate next step in management?