Dislocation of the pituitary gland by sphenocavernous meningiomas.

BACKGROUND

Dislocation of the pituitary gland from the sella turcia by tumor has only very rarely been described. To date, only two cases have appeared in the neurosurgical literature.

METHODS

After intraoperative identification of pituitary dislocation in five patients with cavernous sinus meningiomas, a review of our most recent 20 patients with cavernous sinus meningiomas was performed. A subgroup of sphenocavernous meningiomas was identified, as were the associations between pituitary dislocation and the patient's endocrinologic status.

RESULTS

Of 20 consecutive patients with cavernous sinus meningiomas, seven tumors could be subclassified as sphenocavernous meningiomas due to the significant 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 hypopituitarism, whereas there was no evidence of this condition in the two patients with sphenocavernous meningiomas without pituitary dislocation.

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 extension in the sphenoid sinus. The extension of a cavernous sinus meningioma into the sphenoid sinus, and specifically the sella turcica, may be via the intercavernous venous sinuses. The lack of endocrinologic improvement suggests that the hypopituitarism noted in these patients is likely due to disturbance of the pituitary microcirculation with subsequent pituitary ischemia. The possibility of pituitary dislocation in patients with sphenocavernous meningiomas, especially those with panhypopituitarism, should be considered and searched for at the time of surgery.