Autoimmune hepatitis(AIH) has rarely been described as an autoimmune paraneoplastic syndrome of thymoma.This case is the seventh case of AIH revealed by cholestasis few years after the diagnosis of thymoma and the first case treated with chemotherapy alone.We report in this paper a new approach to this rare severe condition.A 29 year-old man presented with chest pain and dyspnea with a history of thymoma surgically removed 4 years ago.CT scan showed the recurrence of an anterior mediastinal mass.Biology showed elevated liver enzymes and profound cholestasis.No sign of viral or toxic hepatitis or bile duct abnormalities were observed.Autoimmune antibodies,except for the anti-nuclear antibody,were negative.Liver biopsy showed active chronic AIH.The patient was diagnosed with recurrent thymoma with AIH and underwent 6 cycles of chemotherapy.A complete response on thymoma and cholestasis was obtained after 10 months of follow-up.Steroids and immunosuppressors are the standard treatment for AIH.The effect of chemotherapy as a specific treatment of this paraneoplastic syndrome needs to be considered. Autoimmune hepatitis (AIH) has been described as an autoimmune paraneoplastic syndrome of thymoma. This case is the seventh case of AIH revealed by cholestasis few few after the diagnosis of thymoma and the first case treated with chemotherapy alone. We report in this paper a new approach to this rare severe condition. A 29 year-old man presented with chest pain and dyspnea with a history of thymoma surgically removed 4 years ago. CT scan showed the recurrence of an anterior mediastinal mass. Biology showed elevated liver enzymes and profound cholestasis . No sign of viral or toxic hepatitis or bile duct abnormalities were observed. Autoimmune antibodies, except for the anti-nuclear antibody, were negative. Liver biopsy showed active chronic AIH. The patient was diagnosed with recurrent thymoma with AIH and underwent 6 cycles of chemotherapy. A complete response on thymoma and cholestasis was obtained after 10 months of follow-up. Steroids and immunosuppressors are the standard treatment for AIH. The effect of chemotherapy as a specific treatment of this paraneoplastic syndrome needs to be considered.