Abstract
Cystic malformations of the posterior cranial fossa are all but arachnoid cysts contained within the general context of the Dandy-Walker complex and may be further classified in two groups on the basis of their embryological origin: anomalies of the anterior membranous area (AMA) and anomalies of the posterior membranous area (PMA). Whether the latter group of malformations can be regarded as separate entities is still quite controversial. The present authors give a detailed account of the various embryological stages in the formation of the posterior cranial fossa and its contents and propose the identification of two anomalies derived from a defect of the PMA: the mega cisterna magna (MCM) and the persisting Blake's pouch, a new entity with different MRI features from MCM. Criteria for their recognition are discussed, stressing the capital importance of a differential diagnosis in view of the radically different therapeutic approach.
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References
Altman NR, Naidich TP, Braffman BH (1992) Posterior fossa malformations. AJNR 13:691–724
Amundsen P, Newton TH (1978) Subarachnoid cisterns. In: Newton TH, Potts DG (eds) Radiology of the skull and brain: ventricles and cisterns. Mosby, St Louis, pp 3588–3711
Barkovich AJ (1994) Pediatric neuro-imaging, 2nd edn. Raven Press, New York, pp 177–275
Barkovich AJ, Kjos BO, Norman D, Edwards MS (1989) Revised classification of posterior fossa cysts and cystlike malformations based on the results of multiplanar MR imaging. AJNR 10:977–988
Friede RL (1989) Developmental neuropathology, 2nd edn. Springer, Berlin Heidelberg New York, pp 347–360
Harding BN (1992) Malformations of the nervous system. In: Adams JH, Duchen LW (eds) Greenfield's neuropathology, 5th edn. Arnold, London Melbourne Auckland, pp 521–638
Kollias SC, Ball WS, Prenger EC (1993) Cystic malformations of the posterior fossa: differential diagnosis clarified through embryologic analysis. Radiographics 13:1211
Macchi G, Bentivoglio M (1977) Agenesis or hypoplasia of cerebellar structures. In: Vinken PJ, Bruyn GW (eds) Handbook of clinical neurology, vol 30. North-Holland, Amsterdam New York Oxford, pp 367–393
Raybaud C (1982) Les malformations kystiques de la fosse postérieure. J Neuroradiol 9:103–133
Sarnat HB (1992) Cerebral dysgenesis. Embryology and clinical expression. Oxford University Press, New York Oxford, pp 275–329
Tortori-Donati P, Fondelli MP, Rossi A, Cama A, Carini S, Piatelli GL, Ravegnani M (1994) Malformazioni cistiche della fossa cranica posteriore. Riv Neuroradiol 7:199–207
Tortori-Donati P, Longo M, Fondelli MP, Cama A, Carini S, Rossi A (1996) Malformazioni del cervelletto. In: Tortori-Donati P, Taccone A, Longo M (eds) Malformazioni cranio-encefaliche. (Neuroradiologia) Minerva Medica, Torino, pp 159–207
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Tortori-Donati, P., Fondelli, M.P., Rossi, A. et al. Cystic malformations of the posterior cranial fossa originating from a defect of the posterior membranous area. Child's Nerv Syst 12, 303–308 (1996). https://doi.org/10.1007/BF00301017
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DOI: https://doi.org/10.1007/BF00301017