A Rare Cause of Horner Syndrome: Arteria Lusoria

Horner syndrome is a combination of clinical signs, classically of ipsilateral ptosis, pupillary miosis and facial anhydrosis, secondary to the interruption of the oculosympathetic pathway. The causes include tumour infiltration, compression by a lesion such as an aneurysm, iatrogenic causes and traumatic injuries. This paper presents a case of Horner Syndrome due to a rare cause, a congenital anomaly of the aortic arch, arteria lusoria. A 37 year old, female patient referred to our department with a 4 weeks history of ptosis in the right eye. Her medical history was unremarkable. On examination, there was ptosis at her right eyelid and right pupil was myotic. After the tests and examinations, her clinical problem was decided as a well-known condition named "Horner syndrome". Our patient diagnosed as Horner syndrome secondary to aberrant right subclavian artery (arteria lusoria) which is the most common congenital anomaly of the aortic arch. Horner syndrome may be a result of common arterial anomaly like arteria lusoria. Although, there is still not an exact guideline for the diagnostic approach of Horner syndrome and to follow the diagnostic steps according to the patients’ condition would be helpful to find the definite underlying pathology of Horner syndrome.