Yamashita N, Kamiya K, Nagai H
Department of Neurosurgery, Nagoya City University Medical School.
No Shinkei Geka. 1992 Oct;20(10):1097-101.
We have encountered 9 cases of holoprosencephaly, four of them with abnormalities of the posterior fossa. Three cases of semilobar type had severe cerebellar hypoplasia and a large cyst continuing to the fourth ventricle. They were diagnosed as Dandy-Walker syndrome. A case of lobar type had a relatively mild form of cerebellar hypoplasia and it was thought to be a Dandy-Walker variant. MRI was able to clarify the anatomical relationship of the intracranial construction, for example monoventricle, dorsal sac or large cyst in the posterior fossa, and it was very useful for the diagnosis of these congenital anomalies. All of them showed hydrocephalus and required treatment with ventriculoperitoneal or cyst-peritoneal shunt. With the availability of MRI, easy diagnosis of the mild forms of holoprosencephaly has been facilitated, and accompanying anomalies are also able to be diagnosed. Up to now, the structure of the posterior fossa in holoprosencephaly was thought to be normal. However, several cases of holoprosencephaly accompanied with cerebellar hypoplasia and cystic lesion of the posterior fossa, revealed by MRI or autopsy, have been reported. It was suggested that holoprosencephaly with anomalies of the posterior fossa may be less rare than has been thought, so far.
我们遇到了9例前脑无裂畸形，其中4例伴有后颅窝异常。3例半叶型病例有严重的小脑发育不全，并有一个大囊肿延伸至第四脑室。它们被诊断为丹迪-沃克综合征。1例叶型病例有相对较轻的小脑发育不全形式，被认为是丹迪-沃克变异型。磁共振成像（MRI）能够明确颅内结构的解剖关系，例如单脑室、后颅窝背侧囊肿或大囊肿，对这些先天性异常的诊断非常有用。所有病例均显示脑积水，需要进行脑室腹腔分流术或囊肿腹腔分流术治疗。随着MRI的应用，前脑无裂畸形轻度形式的诊断变得容易，同时伴随的异常也能够被诊断出来。到目前为止，人们认为前脑无裂畸形中后颅窝的结构是正常的。然而，已有报道称，通过MRI或尸检发现了几例伴有小脑发育不全和后颅窝囊性病变的前脑无裂畸形。有人提出，伴有后颅窝异常的前脑无裂畸形可能并不像迄今为止人们认为的那么罕见。
