[Congenital Horner syndrome. Case report].

Horner syndrome is characterized by the following triad of clinical signs: miosis, ptosis and facial anhidrosis. In addition, iris heterochromia, conjunctival injection, facial erythema, congestive nasal mucosa and apparent enophthalmos secondary to the reduction of the palpebral fissure can appear. It is caused by an interruption of the sympathetic pathway that extends from the hypothalamus to the orbit. Because there is no decussation, the signs are homolateral to the lesion. Traditionally, it is classified as congenital and acquired. Occasionally, it is associated with neoplasias such as neuroblastoma. It remains controversial what imaging studies should be requested as a protocolized workup of this neurological syndrome in a patient. We report the case of a 45-day-old infant with congenital Horner syndrome.