Investigation of a cyclopic, human, term fetus by use of magnetic resonance imaging (MRI)

Abstract

Using magnetic resonance imaging (MRI), the internal neural and craniofacial malformations of a cyclopic fetus are described. External facial features were characterized by a tubular proboscis situated above a single eye slit. The brain was recognized as 'pancake' type alobar holoprosencephaly (a condition where the undifferentiated telencephalon partially surrounds a monoventricle). Displacement of some bones that normally contribute to the orbit could be clearly discerned. Absence of neural structures (e.g. falx cerebri, corpus callosum) and missing components of the ethmoid bone indicated a midline deficit. This correlates with proposed theories of cyclopic embryopathy, which suggest that the prechordal plate and the neural crest cells are affected during the third week of gestation in cyclopia.

New Classification Scheme of Proboscis Lateralis Based on a Review of 50 Cases

“…Seventeen cases were identified as hypotelorism, and all cases also presented as holoprosencephaly (Table 3). These cases were all stillborn or died at an early age (Gitlin and Behar, 1960; Schinzel et al, 1984; Nyberg et al, 1987; Souza et al, 1990; Galguera et al, 1996; Chen et al, 1999; Situ et al, 2002; Boahene et al, 2005; Cho et al, 2005; Granto et al, 2005).…”

It's all in your head: new insights into craniofacial development and deformation

“…In addition to forebrain malformations, a spectrum of craniofacial phenotypes are seen in human HPE. The most severe facial malformations consist of cyclopia with a proboscis (Situ et al. 2002).…”

“…In addition to forebrain malformations, a spectrum of craniofacial phenotypes are seen in human HPE. The most severe facial malformations consist of cyclopia with a proboscis(Situ et al 2002).Patients in the middle of the spectrum exhibit lesser degrees of facial dysmorphologies consisting of microopthalmia (small eyes), coloboma (incomplete closure of various eye structures, e.g. iris), hypotelorism (decreased interorbital distance), midface hypoplasia (underdevelopmemt Sequence of Shh expression in a developing chick embryo.…”

Ethmocephaly with amniotic band syndrome

“…The condition is differentiated from cyclopia, a severe form of holoprosencephaly where the two eyes are fused together in a single median orbit 4. Another differential diagnosis was cebocephaly, where a flattened nose with single nostril is located below close-set eyes.…”

“…Clinically, ethmocephaly presents with a proboscis situated above hypoteloric orbits in the midline, microphthalmos, absent nasal structures and lowset malformed ears 3. The condition is closely related to cyclopia, a severe form of holoprosencephaly where the two eyes are fused together in a single median orbit 4. Amniotic band syndrome encompasses asymmetrical congenital malformations due to ring-like constriction bands in the limbs, head, face and occasionally the trunk 5.…”