[Primary empty sella. Incidence in 500 asymptomatic subjects examined with magnetic resonance].

In 500 consecutive patients, aged 11-82 years, who underwent MR imaging of the brain for a variety of conditions not related to pathologic processes of the sellar or juxtasellar regions, the authors detected primary totally empty sella in 28/248 males (11.3%) and in 34/252 females (13.5%). Primary partially empty sella was found in 40/248 males (16.1%) and in 38/252 females (15.1%). A progressive increase in the incidence of the signs of primary empty sella was observed with aging, the increase being more conspicuous in the 5th decade of life in females (37.5%) and in the 6th decade in males (40%). On the whole, signs of primary empty sella were detected in 140/500 cases (38%)--namely, in 9.6% of the subjects under 40 and in 39.9% of those above 40. The incidence of primary empty sella, unrelated to any other clinical condition, seems to support its inclusion into paraphysiologic variants. On the basis of the data reported in literature, the authors consider the factors possibly playing a role in this condition. They seem to be: insufficiency or absence of diaphragma sellae, CSF pressure, and pituitary involution related to aging.