Chronic intermittent headache with blurring of vision since 2 years.
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The large well defined, predominantly homogeneous, sellar-suprasellar lesion is noted involving 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. 1cm sized outpouchings along bilateral superior aspects with mildly indenting and compressing on bilateral thalami (Left >> Right).
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.
- 1. D E Johnsen, W W Woodruff, I S Allen, P J Cera, G R Funkhouser, and L L Coleman, MR imaging of the sellar and juxtasellar regions, http://dx.doi.org/10.1148/radiographics.11.5.1947311
- 2.Jerrold L. Boxerman1, Jeffrey M. Rogg1, John E. Donahue2, Jason T. Machan3, Marc A. Goldman4 and Curt E. Doberstein4, Preoperative MRI Evaluation of Pituitary Macroadenoma: Imaging Features Predictive of Successful Transsphenoidal Surgery, American Journal of Roentgenology. 2010;195: 720-728. 10.2214/AJR.09.4128