Asymptomatic type B right atrial thrombus in a case with protein S deficiency.

Thirty seven year old asymptomatic male underwent routine medical examination which revealed an abnormal mass in the right atrium. Family history was not suggestive of any cardiac or malignant disease. Detailed investigation detected deficiency of protein S, which is a vitamin K dependent protein and a cofactor for activated protein C mediated cleavage of factor Va and VIIIa. The deficiency of protein S predisposes to venous thrombosis. Further investigation revealed that it was an organized calcified thrombus in right atrium occupying almost whole of the cavity. Various approaches including surgical excision, thrombolysis and anticoagulation has been used to manage such thrombosis. However therapeutic approach is still a question of debate. Atriotomy and excision of mass was done using cardiopulmonary bypass.