Agenesis of the internal carotid artery with a trans-sellar anastomosis: CT and MRI findings in late-onset congenital hypopituitarism.

A 29-year-old woman with a history of hypothyroidism since early childhood developed hypopituitarism. CT and MRI revealed anterior pituitary hypoplasia, an ectopic posterior lobe, a Chiari I malformation and agenesis of the right internal carotid artery with a trans-sellar anastomosis. This constellation of findings constitutes a previously unreported association in congenital hypopituitarism of late onset. The usefulness of imaging modalities and the pathogenic implications are also discussed.