An enlarged pituitary gland may be caused by a pituitary tumor or pituitary hyperplasia. It is usually not a brain tumor in the general sense. 1. Pituitary tumor: it is a relatively common benign tumor and common endocrine tumor in clinic. In addition to the general symptoms of increased intracranial pressure such as headache, nausea and vomiting, pituitary tumor may also manifest endocrine abnormalities, such as causing amenorrhea and lactation. When the tumor is relatively large, it may compress the optic nerve, causing visual field defect, partial blindness, or even blindness, which usually requires surgical treatment. 2. Pituitary hyperplasia: it may be physiological pituitary hyperplasia caused by pregnancy and breastfeeding, and it will lead to symptoms related to endocrine function. In this case, the symptoms can be improved with medication. Physiologic hyperplasia usually has a very limited increase in size and does not cause significant pressure symptoms. Pathologic growth is usually rapid and can develop into a large size, which can cause compression of the cranial tissues, resulting in intracranial hypertension or neurologic compression. Pituitary enlargement alone cannot accurately determine whether it is a brain tumor or not, and it needs to be combined with the characteristics of medical history and other examination results to make an accurate judgment, and it is recommended that the patient should consult a doctor in time for diagnosis and treatment.