Horner's syndrome secondary to neuroblastoma

Horner's syndrome is classically characterized by a triad of miosis, partial ptosis and anhidrosis. The etiology is due to an interruption in the sympathetic innervation to the eye. A prompt diagnosis is crucial, given that Horner's syndrome could be a manifestation of a life-threatening condition. A thorough case history and clinical evaluation must be employed to arrive at the diagnosis. An important means for confirming Horner's syndrome is pharmacological testing, which is also used to localize the level where the sympathetic chain is compromised. Following the diagnosis and localization of the lesion, an algorithm should be followed to determine the testing indicated, in order to ascertain the underlying cause of the condition. There is a known association between mediastinal neuroblastoma and preganglionic Horner's syndrome. We present a case of a seven-year-old boy with a history of excision of a mediastinal neuroblastoma at age two, who soon after presented with signs and symptoms associated with a residual Horner's syndrome.