The difference between a pituitary tumor and a pituitary adenoma mainly lies in the extent of the affected tissue involved. Generally, pituitary tumors may have a broader range than pituitary adenomas, meaning that pituitary tumors include pituitary adenomas. Normally, a pituitary adenoma specifically refers to tumors occurring in the anterior lobe of the pituitary gland, as this lobe primarily consists of glandular tissue. Meanwhile, the posterior lobe of the pituitary is mainly neurohypophysis. Therefore, tumors typically referred to as pituitary adenomas occur in the anterior lobe. If a tumor is in the posterior lobe, it cannot be called a pituitary adenoma, but it still falls under the category of pituitary tumors.