HI Dr. What is the difference between a simple Pineal cyst and a complex Pineal Cyst. Looks like my MRI showed a 1.3 CM Complex Pineal Cyst. Thank you?

Liquid vs other stuf. A simple cyst generally contains only fluid. A complex cyst is a sac that contains mostly fluid (liquid) but also some material - cells / tissue or colloid or something solid - inside. That solid material makes its appearance different than just a fluid-filled sac. Larger (> 1cm) cysts in the pineal gland can't be distinguished from cystic tumors & so repeated scans are generally the rule. TTYD.