DISLOCATION OF THE PITUITARY-GLAND BY SPHENOCAVERNOUS MENINGIOMAS

BACKGROUND Dislocation of the pituitary gland from the sella turcica b y tumor has only very rarely been described, To date, only two cases h ave appeared in the neurosurgical literature. METHODS After intraopera tive identification of pituitary dislocation in five patients with cav ernous sinus meningiomas, a review of our most recent 20 patients with cavernous sinus meningiomas was performed. A subgroup of sphenocavern ous meningiomas was identified, as were the associations between pitui tary dislocation and the patient's endocrinologic status. RESULTS Of 2 0 consecutive patients with cavernous sinus meningiomas, seven tumors could be subclassified as sphenocavernous meningiomas due to the signi ficant amount of tumor extension into the sphenoid sinus. At the time of surgery, dislocation of the pituitary gland from the sella into the suprasellar cistern was observed in five of seven of these patients. Four of the five patients with pituitary dislocation had evidence of h ypopituitarism, whereas there was no evidence of this condition in the two patients with sphenocavernous meningiomas without pituitary dislo cation. CONCLUSIONS Pituitary dislocation in these patients is likely due to the physical dislocation of the pituitary gland from the sella, through an incompetent diaphragma sella, and by the tumorous extensio n in the sphenoid sinus. The extension of a cavernous sinus meningioma into the sphenoid sinus, and specifically the sella turcica, may be v ia the intercavernous venous sinuses. The lack of endocrinologic impro vement suggests that the hypopituitarism noted in these patients is li kely due to disturbance of the pituitary microcirculation with subsequ ent pituitary ischemia. The possibility of pituitary dislocation in pa tients with sphenocavernous meningiomas, especially those with panhypo pituitarism, should be considered and searched for at the time of surg ery.