An 80-year-old man came for weakness, mild cough and weight loss in two months, he is hypertensive BHP taking drugs regularly. H/o such illness 30 years back treated for two months. Now ESR 119 CBC normal, blood sugar normal ECG normal. X-ray HRCT attached.

X-ray chest shows two fluid filled thin walled cavities. No sputum available till today. What further investigation required for left lung?