Isolated rhomboencephalosynapsis – a rare cerebellar anomaly.

Abstract

SummaryBackground:Rhomboencephalosynapsis (RES, RS) is a unique entity usually recognized in infancy based on neuroimaging. Cerebellar fusion and absence of cerebellar vermis is often associated with supratentorial findings. Since now there are about 50 cases described worldwide, with approximately 36 patients diagnosed by MRI. The authors present the first in Poland case of this uncommon malformation and review the literature.Case Report:The authors describe a 28-month-old-girl with microcephaly and proper psychomotor development. The family history was unrelevant. Based on MRI the congenital malformation of posterior fossa-rhombencephalosynapsis was confirmedConclusions:Presented patient is a typical example of MRI usefulness especially in patients with RES. RES symptoms are mild and that is why the diagnosis is usually made only in adulthood.

Rhombencephalosynapsis - wada izolowana lub częściej złożona

“…Another feature of our patient was a dilated supratentorial ventricular system that is often associated with RES and results from the stenosis of aqueduct of Sylvius [3,8]. Only one child in our group did not show a dilated ventricular system and it was the only case of the isolated malformation – as in the case described by Paprocka et al [5]. The remaining 7 patients described in this paper had other accompanying anomalies: underdevelopment of corpus callosum in 3 cases, abnormalities of gyration in 2, brainstem hypoplasia in 2, isolated fourth ventricle in 1, abnormal white matter signal intensity in 4 (in 2 cases in supratentorial compartment, in 1 in the cerebellum and in 1 in the pons – Figure 2), abnormally dilated extraaxial fluid collections in 2, syringohydromyelia in 2.…”

“…The incidence rate of this anomaly is about 0,13% [ 4 ]. There is only one description of this anomaly in Polish literature [ 5 ]. Over the period of 7 years 8 cases of rhombencephalosynapsis have been diagnosed in two pediatric centers in Warsaw, including the one diagnosed during prenatal magnetic resonance imaging (MRI).…”

Successfully treated symptomatic fusiform basilar artery aneurysm in a patient with hindbrain malformation via inverted Y-stenting

“…It is postulated to be a primary failure of vermian differentiation2 3 and consists of fusion of the cerebellar hemispheres, dentate nuclei, and superior cerebellar peduncles, and hypogenesis/agenesis of the vermis. In addition to cerebellar dysmorphism, the condition is associated with other neurologic findings including aqueductal stenosis leading to congenital hydrocephalus, ventriculomegaly, dysgenesis of the corpus callosum, and various abnormalities of the thalamus, septum pellucidum, temporal lobes, olivary nuclei, optic chiasm, posterior pituitary, and hippocampus 2 3. Although rhombencephalosynapsis has also been associated with ophthalmologic abnormalities,2 our patient did not exhibit ocular dysfunction early in life and only became symptomatic as the basilar dolichoectasia transformed into a fusiform aneurysm, rather than from the underlying hindbrain malformation itself.…”

Rhombencephalosynapsis, The Famous Unknown: Own Experience and Literature Review of Prenatal Diagnosis with Sonography and Magnetic Resonance Imaging

“…In our case series, case 3 was casually detected in a 26 week -pregnant woman undergoing US for a vaginal bleeding. The other few cases of an isolated RES reported in the literature have been detected postnatally [42].…”

“…Only Koprivek [28] reported a case of a prenatal diagnosis of partial isolated RES that at 12 months of age showed a slight delay in psychomotor development, mild hypotonia with normal cognitive development. Other [42] reported cases diagnosed postnatally, with significant neurologic symptoms such as irritability, poor balance, head rolling, abnormal eye movement, spasticity, dysarthria, strabismus, mild truncal ataxia, self-mutilation, and obsessivecompulsive disorder.…”