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A 60 year old previously healthy man reports new headache and blurred vision. Visual acuity is normal but visual fields show bitemporal hemianopia. Brain MRI looks like this.
What does this image show?
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The arrow is pointing to an area of high signal on this sagittal pre-contrast T1-weighted MRI scan. That white area lies within a mass that appears to
arise within the sella turcica. No separate pituitary gland is visible, so likely the mass is the pituitary gland itself—a pituitary adenoma.
Bright signal on pre-contrast T1 MRI can be caused by fat, protein, some forms of calcium, melanin, slowly-flowing intravascular blood, and methemoglobin from fresh extravascular blood. In this case, it is extravascular blood within the pituitary gland, a phenomenon called “pituitary apoplexy.” This phenomenon occurs most commonly in the setting of a pituitary adenoma, but also without apparent cause, in systemic hypertension, in anticoagulated patients, in the post-partum period (“Sheehan syndrome”), after cardiac surgery, and in head trauma. The bleeding may expand the gland to cause pressure on the diaphragma sellae (causing headache), on the optic chiasm (causing bitemporal hemianopia), and on the cavernous sinus (causing ophthalmoplegia). Transsphenoidal surgery is usually performed promptly--often with excellent restoration of vision and normal ocular alignment. However, pituitary hypofunction often persists.
Bright signal on pre-contrast T1 MRI can be caused by fat, protein, some forms of calcium, melanin, slowly-flowing intravascular blood, and methemoglobin from fresh extravascular blood. In this case, it is extravascular blood within the pituitary gland, a phenomenon called “pituitary apoplexy.” This phenomenon occurs most commonly in the setting of a pituitary adenoma, but also without apparent cause, in systemic hypertension, in anticoagulated patients, in the post-partum period (“Sheehan syndrome”), after cardiac surgery, and in head trauma. The bleeding may expand the gland to cause pressure on the diaphragma sellae (causing headache), on the optic chiasm (causing bitemporal hemianopia), and on the cavernous sinus (causing ophthalmoplegia). Transsphenoidal surgery is usually performed promptly--often with excellent restoration of vision and normal ocular alignment. However, pituitary hypofunction often persists.
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