Blondiaux Eléonore, Valence Stéphanie, Friszer Stéphanie, Rodriguez Diana, Burglen Lydie, Ducou le Pointe Hubert, Blouet Marie, Garel Catherine
Department of Radiology, Hôpital Trousseau, Hôpitaux Universitaires de l'Est Parisien, Université Pierre et Marie Curie, Paris, France.
Fetal Diagn Ther. 2019;45(3):197-204. doi: 10.1159/000475989. Epub 2017 Jul 5.
To describe the prenatal imaging findings in pontine tegmental cap dysplasia (PTCD), a rare congenital malformation of the hindbrain so far reported postnatally only and characterized by a typical appearance of the pons with malformations of the vermis and the cerebellar peduncles.
This retrospective multicenter study retrieved 4 cases of PTCD over a 10-year period. Prenatal ultrasonography and fetal magnetic resonance imaging (MRI) findings were reviewed and compared to postnatal or postmortem data.
In all cases, the parents were referred between 22 and 27 weeks of gestation for characterization of a small cerebellar diameter <3rd centile. The prenatal diagnosis of PTCD was suspected in 1/4 cases, while in 3/4 cases the suggested prenatal diagnosis was pontocerebellar hypoplasia. In all cases, PTCD was characterized by ventral pontine hypoplasia with absence of bulging of the pons and by the tegmental cap protruding into the fourth ventricle on prenatal MRI. Parents opted for termination of pregnancy in 1 case. In the 3 other cases, the children presented with global developmental delay and multiple cranial nerve impairment.
PTCD is a differential diagnosis of pontocerebellar hypoplasia and should be discussed on prenatal MRI in the presence of the tegmental cap protruding into the fourth ventricle.
描述脑桥被盖部发育不全（PTCD）的产前影像学表现，PTCD是一种罕见的后脑先天性畸形，迄今为止仅在出生后有报道，其特征为脑桥呈现典型外观，同时伴有蚓部和小脑脚畸形。
这项回顾性多中心研究在10年期间检索到4例PTCD病例。对产前超声和胎儿磁共振成像（MRI）结果进行回顾，并与出生后或尸检数据进行比较。
所有病例中，孕妇在妊娠22至27周期间因小脑直径小于第3百分位数而前来就诊。4例中有1例产前怀疑诊断为PTCD，而4例中有3例产前提示诊断为脑桥小脑发育不全。所有病例中，PTCD的特征为产前MRI显示脑桥腹侧发育不全，脑桥无膨出，且被盖部突入第四脑室。1例父母选择终止妊娠。其他3例患儿表现为全面发育迟缓及多发颅神经损害。
PTCD是脑桥小脑发育不全的鉴别诊断之一，在存在被盖部突入第四脑室的情况下，应在产前MRI上进行讨论。
