Large benign pineal cysts: two case reports with review.

While small benign cysts of the pineal gland are a common incidental autopsy finding in the adolescent and adult years, lesions larger than 0.5 cm in diameter are rare. Cysts 2 cm or larger may cause neurologic symptoms and signs from aqueductal obstruction and tectal compression. Large pineal cysts have an almost 3 to 1 predominance in women, and the high incidence of recent or old bleed into the cyst suggests that it may be a factor in its expansion. In most instances, sequential MRI monitoring of even large, asymptomatic benign pineal cysts remains unchanged, and only rarely is surgical or stereotactic intervention necessary.