Pituitary macroadenoma

Case contributed by Digvijay Rane
Diagnosis almost certain

Presentation

Chronic intermittent headache with blurring of vision since 2 years.

Patient Data

Age: 40 years
Gender: Male
mri

The large well defined, predominantly homogeneous, sellar-suprasellar lesion is noted involving the pituitary gland.

It appears isointense on T1WI and hyperintense on T2WI and FLAIR images with moderate heterogeneous enhancement on post-contrast study.

Slight restricted diffusion is also seen on DWI images.

No e/o obvious blooming is noted on GRE images to suggest internal hemorrhage.

It is causing severe mass effect in form of displacement of bilateral thalami, optic chiasm (Left >> Right) fornices, bilateral ICA, with relative straightening of brain stem.

The mass appears to be encasing the cavernous portion of left ICA, highly suspicious of cavernous sinus invasion on the left side.  

It shows small approx. 1 cm sized outpouchings along bilateral superior aspects with mildly indenting and compressing on bilateral thalami (Left >> Right).

Case Discussion

The incidence of pituitary adenomas is approximately 10% of all intracranial neoplasms. There are two types of adenomas: 

  • microadenomas: those are 10 mm or less in diameter
    • they cause symptoms due to hormonal excess, as their sizes are too small to cause mass effects. Most common microadenoma is prolactinoma, which is associated with prolactin excess. It characterized by amenorrhea and galactorrhea in females. Rests are GH and ACTH producing microadenomas
  • macroadenomas: which are more than 10 mm in diameter, such as in this case
    • as they are larger in size they may cause symptoms due to mass effects. Generally it does not cause hormonal excess symptoms. Owing to its large size, macroadenomas may compress optic chiasm, infundibulum, and hypothalamus as well as can cause erosion of sella turcica. Invasive variant may Infiltrate into adjacent cavernous sinuses, which is commonly assessed by encasement of ICA 1.

MRI features of macroadenomas:

  • T1WI- Isointense to gray matter
  • T2WI- Iso to hyperintense, often variable
  • DWI-May show restricted diffusion (Good transsphenoidal surgical prognosis is observed with pituitary macroadenomas with high diffusivity than with restricted diffusion 2)
  • Post-contrast – Enhancement is common.
  • Hemorrhage can occur in pituitary macroadenomas which is seen as hyperintense on T1WI and blooming on GRE images

Differentials are meningioma, craniopharyngioma, pituicytoma and GCT.

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