MR Imaging Diagnosis of Diencephalic-Mesencephalic Junction Dysplasia in Fetuses with Developmental Ventriculomegaly

Abstract

Diencephalic-mesencephalic junction dysplasia is a rare malformation characterized by a poorly defined junction between the diencephalon and the mesencephalon, associated with a characteristic butterfly-like contour of the midbrain (butterfly sign). This condition may be variably associated with other brain malformations, including callosal abnormalities and supratentorial ventricular dilation, and is a potential cause of developmental hydrocephalus. Here, we have reported 13 fetuses with second-trimester obstructive ventriculomegaly and MR features of diencephalic-mesencephalic junction dysplasia, correlating the fetal imaging with available pathology and/or postnatal data. The butterfly sign can be clearly detected on axial images on fetal MR imaging, thus allowing for the prenatal diagnosis of diencephalic-mesencephalic junction dysplasia, with possible implications for the surgical management of hydrocephalus and parental counseling.

Prenatal diagnosis of diencephalic‐mesencephalic junction dysplasia: Fetal magnetic resonance imaging phenotypes, genetic diagnoses, and outcomes

“…The diencephalic‐mesencephalic junction dysplasias are a recently described form of forebrain‐midbrain malformation 1–5 . We report here a 12‐year single‐center experience of DMJD, which we believe is the largest case series to date, with 33 cases with DMJD identified on fetal MRI or demonstrated retrospectively and detectable as early as 18 weeks gestational age.…”

“…reported 12 more cases and proposed an MRI‐based two‐category classification system, that is, Type A DMJD defined by hypothalamic–mesencephalic union in the axial plane, and Type B DMJD defined by incomplete thalamic–mesencephalic cleavage in the sagittal plane 2 . A recent report of developmental hydrocephalus using retrospective fetal MRI studies identified 13 male fetuses with DMJD as early as 24 weeks gestation; an X‐linked inheritance was proposed but not confirmed 3 . To date, only one adult with DMJD has been reported, with mild cognitive impairment, dysarthria, gait abnormality, deafness, and involuntary trunk movements 5 …”

“…The first report of DMJD in 2012 described an abnormal “butterfly like” midbrain configuration on axial magnetic resonance imaging (MRI) in three consanguineous Egyptian families 1 . Based on the consanguinity and involvement of both sexes in early reports, a novel recessive brain malformation was proposed but not established 2,3 . Recently, the same group reported biallelic pathogenic variants in the nonclustered protocadherin‐12 ( PCDH12 ) gene in all 14 DMJD patients (eight families) studied 4…”

Fetal Ventriculomegaly and Outcomes: About 3 Cases

“…It is most often associated with other abnormalities including rhombencephalosynasis, with agenesis or hypogenesis of vermis, a fusion of dental nuclei and a fusion of the cerebellar lobes [18]. In other cases, mesencephalosynapsis may be associated with thalami and third ventricle fusion with diencephalon mesencephalosynapsis [19].…”

Type‐B Diencephalic‐Mesencephalic Junction Dysplasia Initially Presented With Secondary Cough‐Induced Headaches: A Case Report

“…DMJD has been classified into 2 clinicoradiological patterns: type-A and type-B. 4 Type-A patients present within the first months of life and typically develop severe neurologic dysfunction including axial hypotonia, spastic tetraparesis, dystonic/dyskinetic movements, and severe developmental delay. In addition, some patients had hypothalamic dysfunction.…”