"The National Organization for Rare Disorders says that pineal cysts larger than .50 cm [half a cm] are "rare findings" and are possibly symptomatic. If narrowing of the aqueduct of sylvius occurs, many neurological symptoms may exist, including headaches, vertigo, nausea, eye sensitivity, and ataxia. Continued monitoring of the cyst might be recommended to monitor its growth, and surgery may be necessary."
Pineal cyst symptoms mentioned on various online forums include: severe fatigue, dizziness, memory loss, excruicating headaches and eye pain, migranes, worsening depression, mood swings, neck pain, jaw pain, numbness on side of face, brain fog, blurred vision, worsening eyesight, eye floaters, insomnia, tingling and buzzing in head and body, mixing up words, grand mal seizures.
Many have stated a complete resolution of all symptoms with removal of their pineal cyst. There is a case report of an 8 year old girl experiencing hallucinations due to her pineal cyst. After surgery, the hallucinations went away.