Female, 22 months old, with midline cleft lip and palate with mass in the line of the palatal cleft. A large deficiency is evident in the sphenoid and ethmoid portions of the anterior skull base. Through this deficiency, a CSF filled sac protrudes, continuing through a cleft palate to enter the oral cavity. This CSF filled sac appears to be contiguous with the third ventricle.A small portion of the inferior right frontal lobe herniates partially through the skull base defect. A vascular structure is evident originating at the left aspect of the herniating sac at the level of the nasal cavity, from which point it extends superiorly to join with the internal cerebral veins. The A1 segment of the left ACA also approaches and may slightly enter the defect.The sella turcica is not formed. It appears that the pituitary stalk is elongated and extends down into the defect. The pituitary gland itself appears to be adherent along the posterior wall of the sac, potentially extending as far down as the level of the oral cavity. Some quantity of hypothalamic tissue tracks along the walls of the third ventricle at least partly into the defect.The corpus callosum is absent with resulting colpocephaly. Mild disorganization of the gyri along the inferior frontal lobes is seen. Otherwise, the gyri are unremarkable. No evidence of restricted diffusion or any significant parenchymal signal abnormality is seen.The brainstem and cerebellar vermis are normally formed and intact. The cerebellar hemispheres are unremarkable. A normal variant cisterna magna is demonstrated.Fine bony details of the cleft lip and palate are better assessed on the separately dictated craniofacial CT.
A sphenoethmoidal encephalocele is demonstrated with herniation of a CSF filled sac through the anterior skull base, continuing through a defect in the palate to enter the oral cavity. The CSF filled sac appears to be contiguous with the third ventricle.A very small quantity of the right inferior frontal lobe enters the skull base defect. More notable, however, is the fact that the pituitary gland appears to reside within the herniating sac, positioned along the posterior wall of the sac, potential extending all the way down to the oral cavity. A small amount of hypothalamic tissue may also enter the defect.At least one vascular structure, favored to represent a vein, traverses the encephalocele. The A1 segment of the left ACA approaches and may very minimally enter the defect as well.Brain parenchymal findings are seen compatible with agenesis of the corpus callosum.