Local Effects of Hypothalamic or Pituitary Lesions	

Headaches are caused by local pressure from a tumour and probably result from stretching of the dura mater above the pituitary fossa in a patient with a pituitary tumour (Fig. 2.17). Rarely, they can be caused by a suprasellar tumour (for example, a craniopharyngioma), which compresses the aqueduct of Sylvius and thus prevents the passage of cerebrospinal fluid (CSF) between the third and fourth ventricles. This results in hydrocephalus and enlargement of the third and lateral ventricles. In general, headaches caused by pressure effects are variable in location and are intermittent.