CT and MRI diagnosis of ectopic pituitary adenoma in the sphenoid sinus / 中华放射学杂志

ABSTRACT

Objective To study the CT and MRI findings of ectopic pituitary adenoma in the sphenoid sinus and evaluate their clinical significance. Methods All 8 cases of ectopic pituitary adenoma occurring in the sphenoid sinus were verified by pathology. CT and MRI findings were analyzed retrospectively. Results The lesions occurring in the sphenoid sinus showed no continuity to the intrasellar pituitary gland. The lesions with a well-defined margin showed an oval shape in 3 cases, and an irregular shape in 5 cases. The maximum diameter of the lesions ranged from 20 to 46 mm. On non-enhanced CT, lesion appeared as an isointense mass in 7 cases and a slight hypointense mass in one case. Two cases showed relatively homogeneous moderate enhancement on enhanced CT. The lesions resulted in adjacent bony displacement, remodeling and sclerosis of varying degree. In addition, 5 cases displayed local bony invasion. The bony sellar floor was observed to be intact in 3 cases while bony destruction was displayed in 5 cases. On MR T1WI, ectopic pituitary adenoma revealed isointense signal compared to gray matter in 6 cases and slight hypointense signal in 2 cases. On T2 WI, the lesions showed slight hyperintense singal in 2 cases and isointense signal in 6 cases. The signal of these lesions was inhomogeneous. The stippled and thinly stripped hypointense signal on T1WI and hyperintense signal on T2WI corresponded to the enlarged gland lumen of ectopic pituitary adenoma histopathologically. MR imaging demonstrated mild to moderate inhomogeneous enhancement. A cribriform-like pattern was found on enhanced T1 WI in all of these cases. The time-intensity curve (TIC) of dynamic contrast-enhanced (DCE) MR imaging showed rapidly enhancing and slow washout pattern in 2 cases. The Lesions were found to associate with empty sella in 5 cases, encase adjacent cavernous sinus in 5 cases, and invade the clivus in 4 cases. Conclusions Scattered hyperintense bubbles and strips on MR T2WI and cribriform-like appearance on enhanced T1WI were typical manifestations of ectopic pituitary adenoma in the sphenoid sinus. Combined findings of CT and MRI can provide us with more comprehensive information in both diagnosis and therapy.