RESUMO
Cyclopia is a rare unusual anomaly in which the anterior brain and the midline mesodermal structures develop anomalously. The orbital region is grossly deformed, resulting in the formation of a central cavity [pseudo orbit] with absence of nasal cavity. In the present study, a newly born male goat showing true cyclopia was examined grossly, radiographically, CT and histologically. The head was small and severely deformed with a hydrocephalus on the forehead. The upper and lower lip were present but small. The upper jaw was short due to the absence of the os incisivum and the deformity of the maxilla. A well marked malformed was present. The lower margin of the mandible was strongly curved and carries a prominent ventral peak. The maxilla was reduced. The frontal, lacrimal, nasal, premaxilla vomer bones, the orbit and nasal septum were absent. The dura mater was developed but the falex cerebri was absent. Only one eyeball was present and large with a thick optic nerve. There was only one optic nerve and there was no evidence of optic chiasma Cerebrum was poorly developed and there was no formation of cerebral hemispheres. The eye showed histologically some blood capillaries found in the substantia propria of the cornea. The retina showed areas of normal lamination, whereas in other areas, especially near the site of optic disk, it was replaced by numerous neuronal rosettes. These finding support the hypothesis that the craniofacial malformation in holoprosencephaly result from a developmental disturbance of the mesoderm at the rostral end of the notochord