Pituitary microadenoma

Case contribution: Dr Radhiana Hassan


  • A 28 years old lady
  • Presented with amenorrhoea for one year
  • No blurring of vision, no headache
  • No constitutional symptom
  • Investigation shows hyperprolactinaemia
MRI brain in coronal plane; T1WI, T2WI and T1+Gadolinium
MRI brain in sagittal plane; T1 pre (upper row) and post contrast (lower row)
Coronal MRI pituitary in T1 post contrast

MRI findings:

  • Pituitary gland shows normal size and signal intensity.
  • Posterior lobe is identified at its normal location (blue arrow).
  • However the right side of the lobe shows convex upper border (green arrow) compared to left side which maintains its superior concavity
  • Post contrast dynamic sequence shows a small relatively non-enhancing nodule in the right lobe measuring about 3 mm in diameter.
  • The infundibulum is slightly deviated to the left side, otherwise normal in size and signal intensity
  • No sella expansion
  • No involvement of the optic chiasm

Diagnosis: Pituitary microadenoma


  • MRI is the main imaging for pituitary microadenomas
  • Dedicated pituitary sequences are important for diagnosis (thin slice, small field of view, dynamic contrast acquisition).
  • Contrast-enhanced MRIs have a sensitivity of 90%.
  • On T1 it is usually isointense to normal pituitary
  • T1 dynamic sequences post contrast demonstrate a rounded region of delayed enhancement compared to the rest of the gland
  • Appearance on delayed images are variable, ranging from hypo-enhancement (most common) to isointense to the rest of the gland, to hyperintense (retained contrast)
  • On T2WI it is often variable, but often a little hyperintense


Progress of patient:

  • Hormone level was reduced after medical treatment
  • Patient also has regular menses
  • Repeat MRI shows slight reduction in the size of the pituitary lesion.
Author: radhianahassan