A 32 year old soldier is brought to casualty after a generalised seizure. After awakening he gives history of loss of consciousness twice in the past 2 years. He is otherwise healthy and general physical examination reveals no abnormalities. CT scan with contrast reveals two small hyperintense foci in the right frontal lobe , as well as a 1cm cystic lesion with a nodular focus within it in the left frontal region. The cyst wall of the latter enhances with contrast. The two right lesions do not enhance. The most likely diagnosis?