Empty sella syndrome is a rare disorder characterized by enlargement or malformation of a structure in the skull known as the sella turcica. The sella turcica is a saddle-shaped depression located in the bone at the base of skull (sphenoid bone), in which resides the pituitary gland. In empty sella syndrome, the sella turcica is either partially filled with cerebrospinal fluid and a very small associated pituitary gland lying in the floor of the sella (partially empty sella) or completely filled with cerebrospinal fluid with no visualized pituitary gland (completely empty sella). Most individuals with empty sella syndrome do not have any associated symptoms, but the finding raises concerns about hormone deficiencies. Empty sella syndrome may occur as a primary disorder, for which the cause is unknown (idiopathic), or as a secondary disorder, in which it occurs due to an underlying condition or disorder such as a treated pituitary tumor, head trauma, or a condition known as idiopathic intracranial hypertension (also called pseudotumor cerebri) during which elevated intracranial pressure causes empty sella syndrome.