= rare clinical syndrome of acute hemorrhagic / ischemic transformation of normal / tumorous adenohypophysis

Cause: massive hemorrhage into pituitary adenoma (especially in patients on bromocriptine for pituitary adenoma) / dramatic necrosis / sudden infarction of pituitary gland

Sheehan syndrome = necrosis of anterior pituitary gland ← postpartum infarct ← hemorrhagic shock of complicated delivery

• Only 25% of patients with intratumoral hemorrhage will present with apoplexy!
• severe headache, stiff neck, nausea, vomiting, hypertension
• sudden visual-field defect, ophthalmoplegia
• obtundation (frequent)
• hypopituitarism (eg, secondary hypothyroidism)
  • Area of destruction must be >70% to produce pituitary insufficiency!
• enlargement of pituitary gland

NECT:

• increased density ± fluid level

MR:

• 20% of all pituitary adenomas show evidence of hemorrhage by MR!
• mass lesion of heterogeneous signal intensity:
  • sellar enlargement (= macroadenoma)
  • high signal on DWI (in acute stage) ← restricted diffusion
  • predominant T1 hyperintensity + predominant T2 hypointensity ← hemoglobin
  • intermediate SI on T1WI + T2WI ← deoxyhemoglobin
  • intratumoral fluid-debris level ← sedimentation of blood products (at later stage)
    DDx: Rathke cleft cyst (NO hemorrhage, NO fluid-fluid level)
• mucosal thickening of sphenoid sinus ← venous engorgement of acute stage