易被误诊为垂体腺瘤的淋巴细胞性垂体炎的影像学表现

Imaging findings of lymphocytic hypophysitis easily misdiagnosed as pituitary adenoma

目的探讨淋巴细胞性垂体炎的CT及MRI影像学表现,以期提高对该病影像学诊断的准确率。方法回顾性分析2010年1月至2016年12月首都医科大学附属北京天坛医院神经外科收治的9例淋巴细胞性垂体炎患者的CT和MRI影像学资料。所有患者均行垂体功能相关实验室检查,除2例患者的催乳素水平轻度增高外,余激素水平均正常。9例患者均行MRI检查,其中6例行CT检查,术前影像学诊断均误诊为垂体腺瘤。9例患者均行显微外科手术切除病变。结果9例淋巴细胞性垂体炎患者的MRI影像均表现为垂体弥漫性增大,垂体后叶T1加权像显示高信号消失,蝶鞍扩大,鞍底下陷,鞍底骨质完整;病变以等T1、等T2信号为主;增强扫描呈明显均匀或环形强化,其中5例垂体柄增粗,所有患者均未累及双侧海绵窦。6例行CT检查的患者中,4例病变中心呈低密度,周围呈等密度,2例病变为均匀等密度。9例患者术后均经病理学检查确诊为淋巴细胞性垂体炎。结论淋巴细胞性垂体炎有其典型的影像学表现,与垂体腺瘤相比,淋巴细胞性垂体炎不破坏鞍底骨质,不累及海绵窦,垂体呈弥漫性增大,形态基本对称。掌握其影像学特征可提高本病影像学诊断的准确率。

Objective To study the imaging features of lymphocytic hypophysitis in order to improve the accuracy of imaging diagnosis of the disease. Methods Imaging findings of 9 patients with lymphocytic hypophysitis admitted to Neurosurgery Department of Beijing Tiantan Hospital, Capital Medical University from January 2010 to December 2016 were retrospectively reviewed. All patients underwent laboratory examinations related to pituitary function. Except for 2 cases of slight increase in prolactin, the levels of other hormones were normal. All patients were examined with pre-contrast and post-contrast T1 weighted MR imaging and non-contrast T2 weighted MR imaging. Six patients received CT scan. Imaging diagnoses were all mistaken as pituitary adenomas. Results All cases showed diffuse enlargement of the pituitary, disappearance of neurohypophysis T1WI high signal and enlarged sella. Lesions showed iso-signal on both T1 and T2 weighted image with strong homogeneous or ring-like enhancement. Pituitary stalk was thickened in 5 cases. None of the cavernous sinus was involved in those cases. Lymphocytic hypophysitis was confirmed by pathologic examinations in all 9 patients. Conclusions Lymphocytic hypophysitis seems to have characteristic imaging findings. Compared with pituitary adenoma, lymphocytic hypophysitis does not destroy the sellar floor bone with no involvement of the cavernous sinus and it has diffuse pituitary enlargement and basically symmetrical shape. Those imaging findings of lymphocytic hypophysitis may help us improve the accuracy of imaging diagnosis.