Thomas Kau1,2, Robert Marterer3, Raimund Kottke4, Robert Birnbacher5, Janos Gellen6,7, Eszter Nagy3, Eugen Boltshauser8. 1. Institute of Radiology, Villach General Hospital, Villach, Austria. thomas.kau@kabeg.at. 2. Division of Pediatric Radiology, Department of Radiology, Medical University of Graz, Graz, Austria. thomas.kau@kabeg.at. 3. Division of Pediatric Radiology, Department of Radiology, Medical University of Graz, Graz, Austria. 4. Section of Neuroradiology, Department of Diagnostic Imaging and Intervention, University Children's Hospital Zurich, Zurich, Switzerland. 5. Department of Pediatrics and Adolescent Medicine, Villach General Hospital, Villach, Austria. 6. Division of Obstetrics and Maternal Fetal Medicine, Department of Gynecology and Obstetrics, Medical University of Graz, Graz, Austria. 7. Department of Gynecology and Obstetrics, Villach General Hospital, Villach, Austria. 8. Department of Pediatric Neurology, University Children's Hospital Zurich, Zurich, Switzerland.
Abstract
PURPOSE: The clinical variability of Blake's pouch cysts (BPC) may range from asymptomatic via ataxia to sequelae of decompensated hydrocephalus. On the other hand, Dandy-Walker malformation (DWM) and cerebellar vermis hypoplasia generally correlate with less favorable neurologic development. The aim was to illustrate the potential of prenatal and postnatal neuroimaging to distinguish a BPC or persistent BP from other posterior fossa malformations. METHODS: This pictorial review addresses the inconsistent nomenclature, clinical features, and magnetic resonance imaging (MRI) patterns of BPC and five differential diagnoses. The MRI findings of 11 patients, acquired at up to 3 T in 3 institutions, are demonstrated. Furthermore, the literature was searched for recent improvements in genetic and embryological background knowledge. RESULTS: Posterior fossa malformations often resemble each other and may even be imitated by sequelae of hemorrhagic, ischemic or infectious disruptions, i.e. congenital anomalies of morphology despite normal developmental potential. Hydrocephalus is a typical, albeit not always congenital finding in BPC. It is frequently associated with cerebellar disruptions and DWM; however, it is also a rare complication of posterior fossa arachnoid cysts. A moderately elevated vermis needs follow-up to confirm persistent BP versus vermian hypoplasia or DWM. The fetal cerebellar tail, previously assumed to be specific for DWM, may be imitated in cases of persistent BP. CONCLUSION: The accurate diagnosis of isolated BPC is not always straightforward, which is especially critical in the context of fetomaternal medicine. A detailed description of posterior fossa malformations is to be preferred over unspecific terminology.
PURPOSE: The clinical variability of Blake's pouch cysts (BPC) may range from asymptomatic via ataxia to sequelae of decompensated hydrocephalus. On the other hand, Dandy-Walker malformation (DWM) and cerebellar vermis hypoplasia generally correlate with less favorable neurologic development. The aim was to illustrate the potential of prenatal and postnatal neuroimaging to distinguish a BPC or persistent BP from other posterior fossa malformations. METHODS: This pictorial review addresses the inconsistent nomenclature, clinical features, and magnetic resonance imaging (MRI) patterns of BPC and five differential diagnoses. The MRI findings of 11 patients, acquired at up to 3 T in 3 institutions, are demonstrated. Furthermore, the literature was searched for recent improvements in genetic and embryological background knowledge. RESULTS: Posterior fossa malformations often resemble each other and may even be imitated by sequelae of hemorrhagic, ischemic or infectious disruptions, i.e. congenital anomalies of morphology despite normal developmental potential. Hydrocephalus is a typical, albeit not always congenital finding in BPC. It is frequently associated with cerebellar disruptions and DWM; however, it is also a rare complication of posterior fossa arachnoid cysts. A moderately elevated vermis needs follow-up to confirm persistent BP versus vermian hypoplasia or DWM. The fetal cerebellar tail, previously assumed to be specific for DWM, may be imitated in cases of persistent BP. CONCLUSION: The accurate diagnosis of isolated BPC is not always straightforward, which is especially critical in the context of fetomaternal medicine. A detailed description of posterior fossa malformations is to be preferred over unspecific terminology.
Entities:
Keywords:
Arachnoid cyst; Cerebellar disruption; Cerebellar hypoplasia; Dandy-Walker malformation; Mega cisterna magna