Introduction: Pourfour du Petit syndrome, rarely reported, is the opposite of Claude Bernard-Horner syndrome.
Exegeses: A 67 years old female is hospitalised for dysphagia, allowing the discovery of oesophagus carcinoma with mediastinal, pleural and costal extension. The discovery of left unilateral mydriasis associated with exophthalmos and eyelid retraction suggest Pourfour du Petit syndrome; this diagnosis is confirmed by CT-scan, finding pedicular lysis of high dorsal vertebras and intra-canalar tumoral extension.
Conclusion: Pourfour du Petit syndrome has the same localisation value and the same aetiologies as Claude Bernard-Horner syndrome, but its mechanism proceeds byan exciting lesion of cervical sympathetic nervous system. The recognition of this entity can allow the diagnosis of pathologies that need emergency treatment.