web contact: pietsch@indiana.edu


Rhombencephalosynapsis (RHS) is a rare congenital condition in which the cerebellum is severely underdeveloped. According to Savolaine et al, who first observed RHS with MRI, only fourteen cases have been reported since its discovery in 1914. The rhombencephalon is the embryonic hindbrain rudiment, from which the cerebellum buds off (as the metencephalon) and differentiates. In RHS the central part of the cerbellum (vermis) fails to develop and the two cerebellar hemispheres fuse into a single mass: Thus 'synapsis', which implies fusion.

This search was conducted at Indiana University, Bloomington, Indiana and is presented with the generous co-operation and kind permission of SilverPlatter.

MEDLINE EXPRESS (R) 1991-1995 1 of 7

TI: [Rhombencephalosynapsis]

TO: Rhombenzephalosynapsis.

AU: Boltenstern-M; Konrad-A; Jost-W; Uder-M; Kujat-C

AD: Institut fur Neuroradiologie, Universitatskliniken des Saarlandes, Homburg/Saar.

SO: Rofo-Fortschr-Geb-Rontgenstr-Neuen-Bildgeb-Verfahr. 1995 Jul; 163(1): 91-3

ISSN: 0936-6652

PY: 1995



MESH: Abnormalities,-Multiple-pathology; Abnormalities,-Multiple-radiography; Child,-Preschool; Cranial-Fossa,-Posterior; Hydrocephalus-pathology; Hydrocephalus-radiography; Magnetic-Resonance-Imaging; Rhombencephalon-pathology; Rhombencephalon-radiography; Tomography,-X-Ray-Computed

MESH: *Rhombencephalon-abnormalities

TG: Case-Report; Human; Male


AN: 95352804

UD: 9511

MEDLINE EXPRESS (R) 1991-1995 2 of 7

TI: Uncommon posterior cranial fossa anomalies: MRI with clinical correlation.

AU: Demaerel-P; Kendall-BE; Wilms-G; Halpin-SF; Casaer-P; Baert-AL

AD: Department of Radiology, University Hospitals, Leuven.

SO: Neuroradiology. 1995 Jan; 37(1): 72-6

ISSN: 0028-3940

PY: 1995



AB: The clinical and MRI findings in two cases of rhombencephalosynapsis (RS) and two of tectocerebellar dysraphia (TCD) with an associated occipital encephalocele were studied to elucidate the clinical picture and embryogenesis of these rare anomalies. To our knowledge, only one case of TCD [1] and four of RS [2, 3] examined by MRI during life have been reported. The clinical picture in the cases of RS was rather constant and there were similarities with TCD. Consideration of the embryogenesis of the neural tube suggests a temporal proximity of the abnormalities, with TCD arising at a slightly earlier time.

MESH: Cerebellum-pathology; Child-; Child,-Preschool; Cranial-Fossa,-Posterior-abnormalities; Cranial-Fossa,-Posterior-pathology; Infant-; Neurologic-Examination; Rhombencephalon-pathology

MESH: *Cerebellum-abnormalities; *Encephalocele-diagnosis; *Magnetic-Resonance-Imaging; *Rhombencephalon-abnormalities; *Tomography,-X-Ray-Computed

TG: Case-Report; Human; Male


AN: 95223464

UD: 9507

MEDLINE EXPRESS (R) 1991-1995 3 of 7

TI: Antenatal ultrasound diagnosis of cerebellar vermian agenesis in a case of rhombencephalosynapsis.

AU: Litherland-J; Ludlam-A; Thomas-N

AD: Department of Diagnostic Radiology, North Manchester General Hospital, England.

SO: J-Clin-Ultrasound. 1993 Nov-Dec; 21(9): 636-8

ISSN: 0091-2751

PY: 1993



MESH: Abnormalities-classification; Adult-; Cerebellum-pathology; Fetal-Diseases-pathology; Pregnancy-; Rhombencephalon-pathology

MESH: *Cerebellum-abnormalities; *Cerebellum-ultrasonography; *Fetal-Diseases-ultrasonography; *Rhombencephalon-abnormalities; *Ultrasonography,-Prenatal

TG: Case-Report; Female; Human


AN: 94043803

UD: 9402

MEDLINE EXPRESS (R) 1991-1995 4 of 7

TI: Magnetic resonance imaging of normal and abnormal brain development.

AU: Barkovich-AJ; Maroldo-TV

AD: Department of Radiology, University of Carlifornia, San Francisco.

SO: Top-Magn-Reson-Imaging. 1993 Spring; 5(2): 96-122

ISSN: 0899-3459

PY: 1993



AB: Magnetic resonance imaging (MRI) improves our ability to assess brain development and to detect anomalies of brain formation. MRI allows the assessment of brain development by analysis of the effects of myelination on the T1 and T2 relaxation times of the pediatric brain. This article discusses specific imaging strategies and the normal progression of signal intensity changes. Familiarity with this evolution of signal changes allows an estimation of the approximate stage of brain development. High-resolution multiplanar MRI provides good anatomic detail, with excellent distinction between gray and white matter. This technique allows improved detection of many classes of abnormalities of brain formation, some of which were previously detectable only at autopsy. These malformations and their imaging characteristics are discussed under the headings of: corpus callosal dysgenesis, intracranial lipomas, holoprosencephalies, septooptic dysplasia, the cephaloceles, the Chiari malformations, the Dandy-Walker complex, the cerebellar anomalies including Joubert's syndrome, and rhombencephalosynapsis, and the spectrum of neuronal migration anomalies.

MESH: Brain-pathology; Brain-Diseases-pathology; Corpus-Callosum-pathology; Infant-; Infant,-Newborn; Magnetic-Resonance-Imaging

MESH: *Brain-abnormalities; *Brain-growth-and-development

TG: Human


AN: 93349505

UD: 9311

MEDLINE EXPRESS (R) 1991-1995 5 of 7

TI: MRI and clinical findings in rhombencephalosynapsis.

AU: Simmons-G; Damiano-TR; Truwit-CL

AD: Department of Radiology, Fitzsimons Army Medical Center, Aurora, CO 80045-5000.

SO: J-Comput-Assist-Tomogr. 1993 Mar-Apr; 17(2): 211-4

ISSN: 0363-8715

PY: 1993



AB: Rhombencephalosynapsis is an unusual disorder characterized predominantly by agenesis/hypogenesis of the cerebellar vermis and fusion of the cerebellar hemispheres. Three cases are reported with emphasis on the MRI and clinical findings. Discussion of the relative importance of the cerebellar anomalies and associated supratentorial abnormalities is included.

MESH: Abnormalities,-Multiple; Adult-; Cerebellar-Nuclei-abnormalities; Cerebellar-Nuclei-pathology; Cerebellum-abnormalities; Cerebellum-pathology; Cerebral-Ventricles-abnormalities; Cerebral-Ventricles-pathology; Child-; Child,-Preschool; Corpus-Callosum-abnormalities; Corpus-Callosum-pathology; Inferior-Colliculus-abnormalities; Inferior-Colliculus-pathology; Rhombencephalon-pathology; Superior-Colliculus-abnormalities; Superior-Colliculus-pathology

MESH: *Magnetic-Resonance-Imaging; *Rhombencephalon-abnormalities

TG: Case-Report; Female; Human; Male


AN: 93203458

UD: 9306

MEDLINE EXPRESS (R) 1991-1995 6 of 7

TI: MR imaging of rhombencephalosynapsis: report of three cases and review of the literature.

AU: Truwit-CL; Barkovich-AJ; Shanahan-R; Maroldo-TV

AD: Department of Radiology, University of California, San Francisco 94143-0628.

SO: AJNR-Am-J-Neuroradiol. 1991 Sep-Oct; 12(5): 957-65

ISSN: 0195-6108

PY: 1991



AB: We describe the clinical and MR findings in three cases of rhombencephalosynapsis, a rare congenital malformation of the posterior fossa consisting of vermian agenesis or severe hypogenesis, fusion of the cerebellar hemispheres, and apposition or fusion of the dentate nuclei. Associated anomalies include hydrocephalus, fusion of the inferior colliculi, deficiency or absence of the septum pellucidum, and hypoplasia of the anterior commissure. Fourteen previous cases of rhombencephalosynapsis have been reported including Obersteiner's first report in 1914. The clinical presentation is variable, ranging from early death to variable degrees of cerebellar dysfunction and developmental delay. Patients may reach young adulthood. We report three additional cases and provide radiographic (MR) images of this unusual anomaly detected during life. Diagnoses in three children with rhombencephalosynapsis were made on the basis of MR findings. To our knowledge, this is the first report of this disorder being diagnosed in living patients.

MESH: Abnormalities,-Multiple-diagnosis; Brain-pathology; Cerebellum-abnormalities; Child-; Child,-Preschool; Hippocampus-abnormalities; Hydrocephalus-complications

MESH: *Brain-abnormalities; *Magnetic-Resonance-Imaging

TG: Case-Report; Female; Human; Male


AN: 92058531

UD: 9202

MEDLINE EXPRESS (R) 1991-1995 7 of 7

TI: Isolated rhombencephalosynapsis diagnosed by magnetic resonance imaging.

AU: Savolaine-ER; Fadell-RJ; Patel-YP

AD: Department of Radiology, Medical College of Ohio, Toledo 43699.

SO: Clin-Imaging. 1991 Apr-Jun; 15(2): 125-9

ISSN: 0899-7071

PY: 1991



AB: A case of human rhombencephalosynapsis diagnosed in vivo by magnetic resonance imaging (MRI) is presented that demonstrates fusion of the dentate nuclei and agenesis of the cerebellar vermis. To our knowledge, this condition in its isolated form has been previously diagnosed only at necropsy. The developmental features of the cerebellum are discussed and correlation with cerebellar function is also presented. Recognition of this anomaly in the living patient may be useful in further understanding the clinical significance of segmentation of the rhombencephalon.

MESH: Adult-; Cerebellum-pathology

MESH: *Cerebellum-abnormalities; *Magnetic-Resonance-Imaging

TG: Case-Report; Female; Human


AN: 92004956

UD: 9201

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web contact: pietsch@indiana.edu