Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 46 5 2008 10 15 437 440 S Forouzannia 1) Department of Cardiovascular Surgery, Afshar Hospital, Shahid Sadooghi University of Medical Scie M Abdollahi 1) Department of Cardiovascular Surgery, Afshar Hospital, Shahid Sadooghi University of Medical Scie S Mirhosseini 1) Department of Cardiovascular Surgery, Afshar Hospital, Shahid Sadooghi University of Medical Scie S Moshtaghion 1) Department of Cardiovascular Surgery, Afshar Hospital, Shahid Sadooghi University of Medical Scie H Hosseini 1) Department of Cardiovascular Surgery, Afshar Hospital, Shahid Sadooghi University of Medical Scie M Jorat 2) Department of Cardiology, Afshar Hospital, Shahid Sadooghi University of Medical Sciences, Yazd, M Moeeni 1) Department of Cardiovascular Surgery, Afshar Hospital, Shahid Sadooghi University of Medical Scie M Karimi-Zarchi 1) Department of Cardiovascular Surgery, Afshar Hospital, Shahid Sadooghi University of Medical Scie 2015 09 28 Reports which describe sick sinus syndrome due to malignant lymphoma have been rare and only eight cases have been reported until now. This is a case of sick sinus syndrome and superior vena cava syndrome secondary to invasion of occult malignant lymphoma of the lung in a 60 years old male. There were no symptoms or signs of malignancy before the first presentation with sick sinus syndrome. Patient was treated with implantation of a permanent pacemaker. SA node involvement by lymphoma should be considered as an etiological factor when sick sinus syndrome of unknown cause is encountered. https://acta.tums.ac.ir/index.php/acta/article/view/3515 https://acta.tums.ac.ir/index.php/acta/article/download/3515/3491