The septum pellucidum is the septum between the bilateral lateral ventricles. The septum has two layers and is composed of fibrous tissue membranes that are separated during fetal life and can be closed after birth in most patients, but some patients do not close completely and form a widened septum pellucidum. If the width of the septum is more than 1 cm, it is called a septal cyst, which is a benign lesion and requires no special treatment. Patients with severe widening of the septum pellucidum may have impaired cerebrospinal fluid circulation, resulting in increased intracranial pressure and symptoms such as headache, nausea, vomiting, blurred vision, etc. Patients with these symptoms are advised to consult with the neurosurgery department of the hospital, and if necessary, surgery can be performed. In addition, larger hyaline septal cysts can also cause seizures. For patients without symptoms, it is recommended to have regular cranial CT or cranial MRI examinations to closely observe changes in the condition.