蝶窦内异位垂体腺瘤的CT和MRI诊断

目的 探讨蝶窦内异位垂体腺瘤的CT和MRI表现,并评价2种影像检查方法的临床应用价值.方法 回顾性分析8例经组织学证实蝶窦内异位垂体腺瘤的影像学资料.8例患者均经CT和MR检查.结果 8例垂体瘤均位于蝶窦,与鞍内垂体不相连;3例呈卵圆形,不规则形5例,病灶最大径20～46 mm,边界均较清楚.CT表现:与脑灰质比较,平扫呈等密度7例,稍低密度1例,其中2例增强呈较均匀中度强化;病变周围的骨质不同程度受压、变形、硬化,其中5例并可见局部侵蚀状破坏;鞍底骨质完整3例,骨质破坏5例.MRI表现:与邻近脑厌质比较,在T1WI呈稍低信号2例,等信号6例,T2WI呈稍高信号2例,等信号6例,病变信号不均匀,内散在小泡状、细条状长T1、长T2信号,对应组织学上扩大的腺泡;增强后病变不均匀低中度强化,外观近似筛网状.2例行MR动态增强扫描,时间-信号强度曲线均为速升缓降璎.5例伴有空蝶鞍,5例包绕邻近海绵窦,与邻近颈内动脉分界不清,4例侵及斜坡.结论 T2WI小泡状、细条状高信号和增强后T1WI筛网状外观是该病的特征性表现.CT和MRI联合使用能够对该病的诊断、治疗提供更全面的信息.

CT and MRI diagnosis of ectopic pituitary adenoma in the sphenoid sinus

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.