Behavioural manifestations of third ventricular colloid cysts.

Three patients with third ventricular colloid cysts manifested disturbances of memory, emotion and personality in the absence of hydrocephalus. All three patients demonstrated significant improvement following removal of the tumours. The symptoms and signs associated with these neoplasms may be attributed to compression or vascular compromise of the diencephalon with disorder of major limbic system structures. Tumour removal should be undertaken in patients with symptoms even in the absence of hydrocephalus, and ventricular shunting may be inadequate as a sole therapeutic measure.