Introduction: Herniation of cerebellar vermis through the foramen magnum, internal hydrocephaly and spina bifida cystica are the major signs of Chiari type II malformation. Spina bifida cystica (1 in 2000 neonates) is very often the first clinical manifestation of the disease.
Aim: To discuss the pathomorphology, clinical picture and possible treatment of this underestimated malformation.
Patients and methods: Lumbosacral spina bifida aperta and flaccid paraplegia of the lower limbs were found in a female newborn. Later on, pneumonia and evidence of markedly expressed internal hydrocephaly were found. At 48 days of age, surgical correction of the meningocele was undertaken. There was a sudden heart and respiratory arrest at the end of surgery but in spite of the cardiopulmonary resuscitation the infant died 24 hours later.
Results: Postmortem pathological examination revealed expressed internal hydrocephaly, small posterior fossa, herniation of vermis and atrophic medulla oblongata; presence of these signs verified the Chiari type II malformation. It is very difficult to diagnose this malformation antemortem without magnetic resonance imaging. Brainstem dysfunction is the most common cause of death in children under 2 years of age with Chiari type II malformation. Its clinical manifestation can be episodic and poorly expressed.
Conclusions: A thorough understanding of this entity (clinical and pathomorphological manifestations) and magnetic resonance imaging are mandatory for the malformation to be diagnosed. Early recognition of symptoms of brainstem compression and a subsequent surgical decompression can decrease the high mortality rate among children with Chiari type II malformation.