永存胚胎漏斗隐窝(PEIR)MRI病例

永存胚胎漏斗隐窝(persisting embryonal infundibular recess，PEIR)是第三脑室底部的罕见发育异常，发病机理尚有争议。 在鞍区和鞍上区囊性病变的鉴别诊断时需考虑到PEIR。

　　PEIR是一种罕见的疾病，可能与膜发生不良有关，有时会漏诊，应纳入鞍区囊性病变的鉴别诊断中。 影像学表现：漏斗状垂体柄，蝶鞍囊肿。内分泌检测正常有助于诊断，一般保守治疗。

　　永存胚胎漏斗隐窝(PEIR)是累及第三脑室底的罕见异常，尤其是垂体和鞍区的漏斗状隐窝。 正常的漏斗隐窝是垂体柄内第三脑室的小漏斗状延伸，由较大的胚胎漏斗状隐窝的残余构成，在发育过程中闭合。 最近PEIR定义为胚胎形态学上永存的漏斗隐窝。

　　AH，腺垂体; AntL，垂体前叶; B-PM，咽喉膜; df，中脑底部; Ect, 外胚层; End, 内胚层; HP，下垂斑; Inf, 漏斗; InfR，漏斗状隐窝; IntL，下垂体中叶; Mes，中胚层; MesE，中脑; NEct，神经外胚层; NH，神经垂体; OC，视交叉; pharyngo-hypophyseal stalk，P-HS，垂体柄; PitS，垂体柄; PosL，后垂体后叶; PrE，前脑; PT，腺垂体结节部;RhE，菱形脑; RP，Rathke囊; SphB，蝶骨; SphS，蝶窦。AH, adenohypophysis; AntL, anterior hypophyseal lobe; B-PM, buccopharyngeal membrane; Df, diencephalon floor; Ect, ectoderm; End, endoderm; HP, hypophyseal placode; Inf, infundibulum; InfR, infundibular recess; IntL, intermediate hypophyseal lobe; Mes, mesoderm; MesE, mesencephalon; NEct, neuroectoderm; NH, neurohypophysis; OC, optic chiasm; P-HS, pharyngo-hypophyseal stalk; PitS, pituitary stalk; PosL, posterior hypophyseal lobe; PrE, prosencephalon; PT, pars tuberalis of the adenohypophysis; RhE, rhombencephalon; RP, Rathke pouch; SphB, sphenoid bone; SphS, sphenoid sinus.

　　The persisting embryonal infundibular recess (PEIR) is a rare anomaly of the floor of the third ventricle with a debated pathogenesis. It can be a cause of misdiagnosis in the case of cystic lesions of the sellar and suprasellar area.

　　PEIR is a rare condition, probably unrecognized and the result of dysembriogenesis, which should be included in the differential diagnosis of cystic sellar lesions. Imaging features (funnel pituitary stalk and cyst in the sella) appear pathognomonic. A normal endocrine evaluation might help in the diagnosis and warrants conservative treatment.

　　The persisting embryonal infundibular recess (PEIR) is a rare anomaly involving the floor of the third ventricle, particularly the infundibular recess of the pituitary gland and the sellar region. The normal infundibular recess is a small funnel-shaped extension of the third ventricle inside the pituitary stalk. It constitutes the remnant of the larger embryonal infundibular recess, which becomes obliterated during development. PEIR has been recently defined as the persistence of the embryonal morphology of the infundibular recess.

　　• Rare anomaly of the 3rd ventricular floor 三脑室底罕见异常

　　• Unknown etiology 病因不明

　　• Can be associated with hydrocephalus or empty sella 可能与脑积水或空蝶鞍有关

　　• Misdiagnosed as cystic sellar lesion or empty sella 被误诊为囊性鞍区病变或空鞍状

　　• CSF leak and meningitis are serious complications after surgery 脑脊液漏和脑膜炎是术后严重并发症

　　IMAGING

　　• Connection between 3rd ventricle and sellar cyst is a pathognomonic sign 第三脑室和鞍区囊肿相延续（两者间存在连接）是其病理标志

　　• Competent diaphragma sella 鞍隔正常

　　• Hypophysis displaced superiorly and stalk in the midline 垂体向上移位，垂体柄居中

　　3D CISS sequence allows the visualization detailed of the PEIR 3D CISS序列可清楚显示PIER的细节

　　图1.病例1. MRI T1W序列，(A)矢状和(B)冠状位图。增强后，(C)矢状和(D)冠状位图，MRI T1W序列。 (E，G，H)三维平衡稳态梯度回波序列的磁共振脑池造影，沿着垂体柄重建(E：矢状位图，G：垂体柄水平轴位图; H：蝶鞍水平轴位图)。 (F)MRI T2W序列，冠状位图。 AH，腺垂体; III Ven，第三脑室; OC，视交叉;PitS, 垂体柄。

　　图2.病例2.增强MRI T1W序列，(A)矢状，(B)轴向和(C)冠状位图。 (D–F)磁共振脑池造影，三维平衡稳态梯度回波序列，沿着垂体柄重建(D：矢状，E：轴位; F：冠状面)。 (G–I)在(G)矢状，(H)轴位和(I)冠状位的CT骨窗。白色箭头指向变薄的鞍背。钙化与部分受侵的残余鞍背一致。 III Ven，第三脑室; OC，视交叉;PitS, 垂体柄。

　　Figure 1. Case 1. MRI T1-weighted sequence before contrast administration, (A) sagittal and (B) coronal section. MRI T1-weighted sequence after contrast administration, (C) sagittal and (D) coronal section. (E, G, H) Magnetic resonance cisternography with three-dimensional balanced steady-state gradient echo sequence, reformatted following the pituitary stalk (E: sagittal section, G: axial at the level of the stalk; H: axial, at the level of the sella). (F) MRI T2-weighted sequence, coronal section. AH, adenohypophysis; IIIVen, third ventricle; OC, optic chiasm; PitS, pituitary stalk.

　　Figure 2. Case 2. MRI T1-weighted sequence after contrast administration, (A) sagittal, (B) axial, and (C) coronal sections. (D–F) Magnetic resonance cisternography with three-dimensional balanced steady-state gradient echo sequence, reformatted following the pituitary stalk (D: sagittal, E: axial; F: coronal planes). (G–I) CT bone window in (G) sagittal, (H) axial, and (I) coronal sections. The white arrows point to the thinned dorsum sellae. The calcifications are consistent with residuals of the partially eroded dorsum sellae. IIIVEn, third ventricle; OC, optic chiasm; PitS, pituitary stalk.

　　图3.正常胚胎发生和PEIR。 (A)在22天大的胚胎中，可辨别下垂体斑。 (B，C)在28天大的胚胎中，Rathke囊内翻开始。 37天后，形成漏斗状隐窝。 (D)在40到60天之间，初级神经垂体位于腺垂体的后方。 (E)在8周大的胚胎中，由于Rathke裂的部分闭塞，腺垂体与咽完全分离，这是咽下垂体柄的起源。 (F)在3个月大的胚胎中，其解剖结构类似于成年的胚胎。 (G)在成年人中，通常存在具有闭塞的漏斗状隐窝的垂体柄。 (H)在PEIR的情况下，隐窝的闭塞开放，并充满了来自第三脑室的脑脊液。

　　Figure 3. Normal embryogenesis and PEIR. (A) In the 22-day-old embryo, the hypophyseal placode can be distinguished. (B, C) In the 28-dayold embryo, the invagination of the Rathke pouch begins; after 37 days, the infundibular recess is formed. (D) Between 40 and 60 days, the rudimentary neurohypophysis is located posterior to the adenohypophysis. (E) In the 8-week-old embryo, the adenohypophysis is completely separated from the pharynx due to the partial obliteration of the Rathke cleft, which gives origin to the pharyngo-hypophyseal stalk. (F) In the 3-month-old embryo, the anatomical configuration is similar to the adult one. (G) In the adult, the pituitary stalk with an obliterated infundibular recess is normally present. (H) In the case of PEIR, the obliteration of the recess is missing and filled with CSF from the third ventricle.

参考文献，PMID：29788483 DOI： 10.1210/jc.2018-00437