SummaryThe empty sella is due to a cyst-like extension of the subarachnoid space into the sella through a congenital incompletness of the sellar diaphragm. Pneumoencephalogram combined with tomography has shown that in our patient the enlarged sella was not occupied by a tumor but by the intrasellar cisterna. Despite the relative paucity of pituitary endocrine abnormalities, pituitary function should be thoroughly evaluated to exclude early endocrine deficiency.