A 50-year-old male patient presented with headaches for two years and progressive vision loss over three months. MRI revealed a pituitary macroadenoma, which are large pituitary tumors that cause symptoms through mass effect. Macroadenomas share characteristics with smaller tumors on MRI, appearing hypointense on T1-weighted images and hyperintense on T2-weighted images. The macroadenoma in this case completely filled the sella turcica. Criteria for determining if a macroadenoma has invaded the cavernous sinus include intact pituitary tissue between the tumor and sinus, an intact medial venous compartment, and less than 25% encasement of the internal carotid artery. Post-operative Gelfo

1. Radiology meet
08-03-2014
R.Rengarajan

2. 50 yr old male patient with
• Headaches on and off for 2 yrs
• Progressive loss of vision for 3 months

8. Pituitary macroadenoma

11. • Pituitary macroadenomas become clinically significant
when they reach the size large enough to cause
symptoms due to mass effect because most, but not
all, macroadenomas are nonfunctioning tumors.
• Therefore, these lesions present late and can achieve
quite remarkable volumes.

12. • Macroadenomas share some of the MR characteristics of their
smaller counterparts.
• MR typically demonstrates a mass arising from the pituitary
fossa, hypointense on T1-weighted images, compressing the higherintensity normal pituitary tissue.
• Macroadenomas are more often hyperintense on T2-weighted
images than are microadenomas. Hyperintensity on the T2weighted images may be useful in predicting that a macroadenoma
is soft or partially necrotic and thus easily removed by suction and
curettage.
• A significant direct correlation has recently been shown between
tumor consistency (hardness) and apparent diffusion coefficient
(ADC) values.

14. • In most instances the macroadenoma completely fills
the sella; the normal tissue is so compressed that it is
virtually obliterated and cannot be identified.
• The posterior pituitary bright spot is seen in an ectopic
location or not at all in the majority of cases.
• The essence of the diagnosis of macroadenomas is the
definition of the lesion as intrinsic to the pituitary
gland.

15. • The other feature to be sought is enlargement of the sella, because
large pituitary adenomas virtually always enlarge the sella due to
their slow growth and late presentation, whereas other intrinsic
pituitary lesions, such as pituitary metastasis and inflammatory
lesions, do not.
• The multiplanar capabilities, lack of bone and surgical clip
artifact, and ability to demonstrate large arterial structures make
MR a powerful tool in the pre- and postoperative assessment of
pituitary macroadenomas

16. • Intratumoral hemorrhage occurs in 20% to 30% of pituitary
adenomas, most often in macroadenomas.
• Although pituitary infarction and/or hemorrhage may result
in the clinical syndrome of pituitary apoplexy, more
frequently hemorrhage is subclinical and is discovered only
incidentally on MR.
• In fact, only a small fraction of these patients has clinical
findings of pituitary apoplexy.
• The incidence of bleeding is much higher in patients
receiving bromocriptine.

17. • Larger pituitary adenomas may be accompanied by cystic
degeneration with or without hemorrhage.
• Cystic degeneration in an adenoma is evident as sharply defined
regions of very low signal intensity on T1-weighted images that are
markedly hyperintense on the T2-weighted sequence.
• A fluid-debris level is a more specific sign of cystic degeneration but
is infrequently present.
• Rarely, noncystic adenomas possess similar signal characteristics
and mimic a cyst.

19. Criteria for non-invasion of cavernous sinus
(1) normal pituitary between the adenoma and cavernous sinus
(positive predictive value 100%),
(2) intact medial venous compartment (positive predictive value
100%), and
(3) less than 25% ICA encasement (negative predictive value 100%).
Despite the fact that cavernous sinus involvement by pituitary
adenomas is not uncommon, marked constriction or occlusion of
the cavernous portion of the internal carotid artery is very rare.

21. • Surgical cavities packed with Gelfoam display variable MR
signal intensities in the immediate postoperative period.
• The most common appearance of Gelfoam was isointensity
to the pituitary gland with an irregular center of decreased
signal intensity on T1-weighted images.
• It may be difficult to distinguish postoperative scarring or
graft material from the normal gland or adenomatous
tissue (especially in the first 6 months after surgery).

22. Thank you