Empty Sella Syndrome Health Article

Definition

Empty sella syndrome is the appearance, by radiograph (x ray) of the skull, that the sella turcica, which normally contains the pituitary gland, is empty.

Description

Sella turcica is Latin for "Turkish saddle," which roughly describes the U–shaped appearance of this bony pocket when seen by x ray. It is a concavity in the middle of the sphenoid bone measuring about 1.5 × 1.0 × 0.5 cm. The sphenoid bone forms a portion of the base of the skull just behind the eyes, at about the midpoint and just below the cerebral hemispheres.

The pituitary gland has a bulbous shape, extending on a stalk below the hypothalamus. The pituitary normally completely fills the sella turcica. The subarachnoid space, filled with cerebrospinal fluid (CSF), surrounds the pituitary stalk. The dura mater (see Meninges) normally extends away from the bony upper portion of the sella turcica forming a barrier between the subarachnoid space and the pituitary gland below. This barrier formed by the dura mater surrounding the top of the pituitary gland is known as the diaphragma sella.

In most cases when an empty sella is seen by x ray, the sella turcica is not truly empty. In fact, CSF has entered the space normally occupied by the pituitary and has compressed the gland against the wall of the sella. A truly empty sella, i.e., missing pituitary gland, is rare.

Demographics

The true incidence of empty sella syndrome in the population is not known. However, statistics collected from autopsies have shown that an empty sella is found as an incidental finding in anywhere from 5% to 25% of cases. These do not include cases in which the pituitary gland was surgically removed or irradiated.

Most cases of empty sella syndrome are seen in middle–aged, obese women, who often have hypertension. Children with empty sella syndrome are more often symptomatic, which most often manifests as growth hormone deficiency. About half of children with growth hormone deficiency are found to have an empty sella, but only 2% of children with normal pituitary function have the finding.