[Secondary empty sella syndrome: report of three cases and review of the literature].

Three cases of the secondary empty sella syndrome were reported. Case 1. A 57-year-old female was admitted to our clinic because of recurrent visual disturbance. Fourteen years previously a pituitary adenoma was diagnosed and two courses of radiation therapy was given elsewhere, the total dosage being unknown. Pneumoencephalography revealed air collection in the sellar cavity. Exploratory craniotomy demonstrated an empty sella with downward migration of the optic nerve and chiasm. Case 2. A 40-year-old female was readmitted to our clinic for possible recurrent pituitary adenoma. Three years previously she underwent transsphenoidal surgery and postoperative radiation therapy with a tumor dose of 6,400 rad. She had headache and visual disturbance. Pneumoencephalography showed air extension into the sellar cavity. Case 3. A 50-year-old female was readmitted to our clinic because of general prostration and headache. Ten years previously she received transsphenoidal surgery and postoperative radiation therapy with a tumor dose of 6,650 rad for a pituitary adenoma. Endocrine evaluation revealed a hypopituitarism. Pneumoencephalography showed air extension into the sellar cavity. The etiology of secondary empty sella has not been clarified yet, although the primary empty sella has been considered to result from incomplete development of the diaphragma sellae. We consider that the most important factor should be present in the diaphragma itself. It is conceivable that the diaphragma sellae becomes weak due to 1) compression by the tumor, 2) mechanical injury during operation, 3) radiation effect. Then, these preceding factors might bring about herniation of the optic nerve and chiasm with the diaphragma sellae into the sellar cavity. Therefore, we propose that early diagnosis of pituitary tumor should be important, and that careful packing of the sellar floor at transsphenoidal surgery should be essential to prevent occurrence of the secondary empty sella syndrome.