Empty sella (ES) is defined as an herniation of the sub-arachnoid space into the selia turcica, which is associated with stretching of the pituitary stalk and flattening of pituitary gland against the sellar floor. The term "empty sella" was first used by Sheehan and Summer in 1949 to describe the empty appearance of the sella turcica at autopsy due to contraction of the pituitary following post-partum pituitary necrosis; subsequently autoptic series of subjects with ES but without any evidence of pituitary disease have been described (1, 2). ES has been classified as either primary or secondary. Secondary ES may be caused either by pituitary adenomas undergoing spontaneous necrosis, infective, vascular, autoimmune, and traumatic causes or by surgery and radiotherapy. Conversely, "primary ES" (PES) is not related to the previously mentioned conditions; the pathogenesis of PES would include congenital incomplete formation of the sellar diaphragm, and supra-sellar causes such as stable or intermittent increase in intracranial pressure. Clearly, the widespread use of computed tomography and magnetic resonance imaging techniques, has made PES a frequent "incidental" finding. Data from autoptic and neu-roradiological studies report ES in a percentage ranging from 5.5 to 35 of subjects, being more frequent in women (female/male:4/1) and in obese subjects (3-6).
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