Hi. Welcome to practo pro. I read your query and understand your concern. Your ultrasound shows that you have a simple cyst (cyst means a fluid filled sac) in your left breast which is nothing to be worried about.
Next Steps
There’s no treatment for this since it is less than 1 cm in size. Simple follow up with surgeon after 1 year is enough. If it is palpable by you on monthly self breast exam, you get general surgeon opinion for it. Simple aspiration of fluid can be done then.
Health Tips
Be reassured that it’s benign. Not cancer or similar conditions that needs treatment.