1 Dicle University Faculty of Medicine, Department of Pediatric, Diyarbakir, Turkey
2 Yüzüncü Yıl University Faculty of Medicine, Department of Pediatric, Van, Turkey Correspondence: Fesih Aktar;
Dicle University Medical Faculty, Department of Pediatric, Diyarbakır, Turkey Email: fesihaktar@yahoo.com Received: 03.05.2016, Accepted: 14.05.2016
Copyright © Archive of Medical Investigations / Tıp Araştırmaları Arşivi 2016, All rights reserved
Archive of Medical Investigations / 2016; 1 (1): 18-20
Tıp Araştırmaları Arşivi doi: 10.5799/ahinjs.03.2016.01.0004
CASE REPORT / OLGU SUNUMU
Isolated Rhombencephalosynapsis: A rare disease
Fesih Aktar1, Kamuran Karaman2, Serap Karaman2, Gökmen Taşkın2, Hüseyin Çaksen2 ABSTRACT
Rhombencephalosynapsis is a rare congenital malformation of the cerebellum characterized by hypogenesis or agen- esis of the vermis and fusion of the cerebellar hemispheres with or without fusion of the dentate nuclei and superior cerebellar peduncles. Clinical presentation and prognosis are variable and are primarily determined by the presence and extent of concomitant supratentorial anomalies. Survival time of cases are generally short and they can rarely survive into early adulthood. A four year-old girl patient presented with incapability to work. Her height, weight and head cir- cumference were <3 percentile. She had psychomotor retardation, microcephaly, broad forehead, and superior lip shift down, dysplastic ear, strabismus, bilateral pes equinovarus and hammer toe in both feet. The deep tendon reflexes were increased and there was spasticity in lower extremities. In brain magnetic resonance imaging; the cerebellar hemisphere was fused on middle line. Cerebellar vermis, septum pellisidium and corpus callosum were not observed. The posterior horns of the lateral ventricle are separated. This case was presented with clinical features because of it is a rarely re- ported disease in literature. Arch Med Invest 2016; 1 (1): 18-20
Key words: Rhombencephalosynapsis, congenital malformation, cerebellum, child
İzole Rombensefalosinapsis: Nadir bir hastalık
ÖZET
Rombensefalosinapsis, vermis agenezisi veya hipogenezisi ve serebellar hemisferlerin dentat nükleus ve superior sere- bellar pedinküller ile birlikte olan veya olmayan füzyonu ile karakterize, nadir görülen serebellumun konjenital bir mal- formasyonudur. Klinik bulgular ve prognoz primer olarak eşlik eden supratentoriyal anomalilere bağlı olarak değişmek- tedir. Olguların yaşam süresi çoğunlukla kısadır ve nadiren erken erişkin döneme kadar yaşarlar. Dört yaşında kız hasta yürüyememe şikâyeti ile getirildi. Boy, vücut ağırlığı ve baş çevresi 3 persentilin altında idi. Hastada psikomotor gerilik, mikrosefali, alın genişliği, üst dudağın aşağı doğru dönük olması, displastik kulak, strabismus, bilateral pes ekinovarus ve her iki ayak başparmaklarında çekiç parmağı vardı. Derin tendon refleksleri artmıştı ve alt extremitelerde spastisitesi mevcuttu. Beyin manyetik rezonans görüntülemede, serebellar hemisfer orta hatta füzyone ve serebellar vermis, septum pellisidium ve corpus callosum izlenmedi. Lateral ventrikülün posterior hornları birbirinden ayrık idi. Literatürde nadir olarak bildirilen bu vakanın klinik özellikleri ile birlikte sunulması amaçlandı.
Anahtar kelimeler: Rhombencephalosynapsis, konjenital malformasyon, serebellum, çocuk
INTRODUCTION
Rhombencephalosynapsis (RES) is a rare congenital malformation of the cerebellum characterized by hy- pogenesis or agenesis of the vermis and fusion of the cerebellar hemispheres with or without fusion of the dentate nuclei and superior cerebellar peduncles [1,2].
Since then, fewer than 100 cases have been reported.
Clinical presentation and prognosis are variable and are primarily determined by the presence and extent of concomitant supratentorial abnormalities [1,2]. This
case has been presented because of it is a rarely re- ported disease in literature.
CASE REPORT
A four year-old girl patient applied for incapacity to walk. Her medical history revealed that she started to talk at age of two, to sit without support at age of three and she still cannot walk. According to her anamnesis, she was born at home by normal spontaneous vaginal
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way on time, she cried immediately after the birth and she did not go through jaundice or cyanosis. There was no particularity in her family history. In physical ex- amination, her height was 75 cm (<3 percentile), her body weight was 8300 gram (<3 percentile), and her head circumference was 48 cm (<3 percentile). She had psychomotor retardation. The patient presented microcephaly, broad forehead, and superior lip shift down, dysplastic ear, strabismus in right eye, bilateral pes equinovarus, and hammer toe in both feet. The deep tendon reflexes were increased and there was spasticity in lower extremities (Figure 1, 2). Hemo- gram, biochemical and urinary analyses, coagulation tests and thyroid hormone, vitamin B12, folate and ferritin levels were normal in laboratory analyses. In brain magnetic resonance imaging, for posterior fossa series evaluation; the cerebellar hemisphere was fused on middle line and the cerebellar vermis was not ob- served (Figure 3). In the evaluation of supratentorial sections; the septum pellisidium was not observed.
The corpus callosum, the corpus posterior and the splenium were not observed (dysgenesis of the corpus callosum). The third and lateral ventricles are dilated.
The posterior horns of the lateral ventricle are sepa- rated (secondary to dysgenesis of the corpus callosum) (Figure 4). Diagnosis of rhombencephalosynapsis has been established according to the radiological find- ings. The electroencephalogram, visually evoked po- tential analysis, brainstem auditory evoked potential, echocardiography, abdomen and urinary system ultra- sonography and skeletal survey analyses performed systematically to determine the association to defects of this syndrome, were normal.
Figure 1. Microcephaly, broad forehead, superior lip shift down, dysplastic ear, strabismus
Figure 2. Bilateral pes equinovarus, hammer toe in both feet and spasticity
Figure 3. Absence of the cerebellar vermis in T2 weighted cross-section
Figure 4. Absence of the septum pellisidium in T1 weighted cross-section, the third and lateral ventricles are dilated secondary to dysgenesis of the corpus callosum and the posterior horns of the lateral ventricle are separated
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DISCUSSION
Common clinical presentations of disease include developmental delay, mild truncal ataxia, epilepsy, spasticity, hypotonicity, strabismus, involuntary head movements, severe motor and cerebellar dysfunction and a few reports of psychiatric disturbances and self- mutilating behaviors [2-4]. Our case presented devel- opmental retard, psychomotor retard, spasticity and strabismus. Multiple authors have reported instances of craniofacial dysmorphism, including hypertelorism, low-set ears, and high arched palate in patients with RES [1,2].
The most commonly reported systemic malfor- mations involved the musculoskeletal system, but abnormalities in the cardiovascular, urinary, and re- spiratory systems occur as well [2,6,7]. Dysmorphism findings such as microcephaly, broad forehead, and superior lip shift down, dysplastic ear, strabismus in right eye, bilateral pes equinovarus, and hammer toe in both feet have been stated. However system analy- ses were normal. Survival time of cases are generally short and they can rarely survive into early adulthood.
Newly diagnosed cases in the adulthood are extremely rare [1,2,7]. Our patient is four year-old and is healthy except his mental retardation.
Rhombencephalosynapsis occurs in response to a disturbance of development of the cerebellum at 28 to 41 days of gestation, a time period consistent with the formation of the supratentorial structures found to be abnormal in patients with RES [1-2]. During nor- mal development, the cerebellar hemispheres arise from two distinct embryonic primordia, known as the rhombic lips. From this perspective, rhombencephalo- synapsis is considered to be abnormal development of the vermis with subsequent fusion of the hemispheres [5,7]. Most of the cases have been reported in children, and almost all cases have been sporadic. Romanengo et al. reported on a patient with RES born to consan- guineous parents and suggested an autosomal reces- sive mode of inheritance, most authors believe that the occurrence of RES is sporadic [8]. To date, however, no genetic or chromosomal abnormalities and no clear pattern of inheritance have been identified for RES [2]. In our case, there is no consanguinity in his parent history.
The diagnosis is established with the magnetic resonance imaging findings. Associated findings on
MRI include; deficiency or absence of the septum pellucidum, dysgenesis of the corpus callosum and the anterior commisure, fused fornices and thalami [5]. Superior and middle cerebellar peduncles, along with dentate nuclei and inferior colluculi, are gener- ally fused, giving rise to the typical diamond-shaped fourth ventricle on axial scans. Aqueductal stenosis is commonly associated, and it represents as congenital hydrocephalus [7]. In our case, the cerebellar hemi- sphere was fused on middle line and the cerebellar vermis, septum pellisidium and corpus posterior and splenium of the corpus callosum were not observed in brain magnetic resonance imaging. Rhombencephalo- synapsis diagnosis has been established according to the radiological findings of our patient who presented dilated third and lateral ventricles, and separated pos- terior horns of the lateral ventricle.
In conclusion, rhombencephalosynapsis has vari- ous clinical presentations, as well as characteristic ap- pearance on magnetic resonance imaging.
Declaration of Conflicting Interests: The authors declare that they have no conflict of interest.
Financial Disclosure: No financial support was received.
REFERENCES
1. Chemli J, Abroug M, Kalthoum T, Abdelaziz H. Rhomben- cephalosynapsis diagnosed in childhood: clinical and MRI findings. Eur J Paediatr Neurol 2007;11:35-38.
2. Toelle S, Yalcinkaya C, Kocer N, et al. Rhombencephalo- synapsis: clinical findings and neuroimaging in 9 children.
Neuropediatrics 2002;33:209-214.
3. Shahrzad M, Gold M. Rhombencephalosynapsis: a rare con- genital anomaly presenting with seizure and developmental delay. Acta Neurol Belg 2015;115:685-686.
4. Passi GR, Bhatnagar S. Rhombencephalosynapsis. Pediatr Neurol 2015;52:651-652.
5. Arisoy R, Erdogdu E, Pekin O, et al. A rare case of rhomben- cephalosynapsis and prenatal diagnosis. J Obstet Gynaecol 2016;25:1-3.
6. Mendonca JLF, Natal MRC, Viana SL, et . Rhomben- cephalosynapsis: CT and MRI findings. Neurology India 2004;52:118-120.al
7. Abdel Razek AA, Castillo M. Magnetic resonance imaging of malformations of midbrain-hindbrain. J Comput Assist Tomogr 2016;40:14-25.
8. Romanengo M, Tortori-Donati P, Di Rocco M. Rhomben- cephalosynapsis with facial anomalies and probable au- tosomal recessive inheritance: a case report. Clin Genet 1997;52:184-186.
