Aplasia of right internal carotid artery and hypopituitarism.

Background. The pathogenesis of congenital hypopituitarism is unknown in many cases. Objective. We report a case of congenital pan-anterior hypopituitarism in association with a complex vascular abnormality involving the central nervous system, nasal pyriform aperture stenosis, and a single central maxillary incisor. Materials and methods. MRI and MRA were used to define this patient's complex vascular anomaly. Results. The vascular abnormality consists of absence of the right common carotid artery, the right internal carotid artery, the A1 segment of the right anterior cerebral artery, the anterior communicating artery, and partial absence of the M1 segment of the right middle cerebral artery. Conclusion. This unusual vascular anomaly may contribute to the pathogenesis of some cases of congenital hypopituitarism and related midline abnormalities, or may result from a common defect that causes pituitary insufficiency.