Headaches may be directly provoked in individuals with a pituitary tumor by entering an area referred to as the cavernous sinus. The cavernous sinus is a region of the brain that houses the first and second trigeminal nerves. Compression of these nerves can cause a headache because they are sizeable cranial nerve bundles that dictate the sensation in the face.
Other pituitary tumor patients may experience headaches when the tumor begins to affect the area of the brain and neck where the meninges are located. Cancer infiltration near or into the meninges can cause inflammation of these membranes, which results in subsequent swelling and pain in the back of the head. Furthermore, individuals who have a pituitary tumor causing the gland to decline in function tend to develop vascular headaches due to the pituitary hormone shortage.