Pituitary macroadenoma


  • A 57-year-old man
  • Presented with headache and diplopia.
  • Clinical examination showed ptosis of left eye with CNIII palsy.
  • There was no body weakness.

Imaging finding:

  • The non-contrast axial plane soft tissue window CT scan of the brain (a) showed a hyperdense lesion at the sella region. There is no calcification within the lesion.
  • Coronal MRI images (b) T1-weighted, (c) T2-weighted and (d) Post contrast image showed a sella lesion with suprasellar extension which is isointense on T1, hyperintense on T2 with minimal contrast enhancement.
  • The classic ‘figure of eight’ or ‘snowman’ appearance demonstrated in this case.
  • Compression and elevation of optic chiasm is also seen.
  • Both carotid arteries were encased within the lesion but patent.

Diagnosis: Pituitary macroadenoma (HPE proven)


  • Pituitary macroadenomas are the most common suprasellar mass in adults.
  • They are defined as pituitary adenomas greater than 10mm in size.
  • Patients typically present with symptoms of local mass effect on adjacent structures especially the optic chiasm.
  • Imaging shows sellar mass without separate identifiable pituitary gland.
  • CT scan shows variable attenuation sella mass usually isodense to gray matter.
  • The best imaging technique for assessment is MRI with sagittal or coronal T1 and T2-weighted images.  On MRI this lesion usually is isointense to gray matter on T1WI and T2WI, most lesion show moderate heterogenous enhancement post contrast but some adenomas can be hypoenhancing.
  • The morphological ‘snowman’ appearance is caused by dural constriction by diaphragm sella.
  • Cysts and necrosis are common occurring in about 15-20% of cases.
  • Hemorrhage can occur in 10% of cases and calcification in 1-2% of cases.


Author: radhianahassan