The case of a potentially life-threatening complication related to the use of implanted port device in a 8 year old Non-Hodgkin's Lymphoma patient receiving chemotherapy is described. The device was inserted in early 1997 and used repeatedly for chemotherapy without any complications. In late 1997 during routine screening for cardiac left ventricular function before re-introduction of chemotherapy, an abnormal 1.43 x 1.53 cm mass, consistent with a non-mobile thrombus was found in the right atrium. The initial thrombolytic therapy with recombinant tissue plasmin activator (rt-PA) infused by a central venous catheter was combined with daily echocardiographic examination in order to assess both the timing and mode of thrombus resolution. After 8 days systemic fibrinolytic therapy was discontinued as major hemorrhage from venipuncture sites occurred and the clot dissolution was not obtained. Patient underwent right atriotomy utilizing cardiopulmonary bypass and subsequent surgical thrombus removal was successful. The study evaluated the contribution of two-dimensional echocardiography (2D) in the follow-up of vascuport and other central venous catheter (CVC) location and early diagnosis of related complications such as thrombi. The authors consider that pulmonary flow analyzed with Doppler echocardiography as a reliable, suitable and non-invasive method to evaluate increased pulmonary artery pressure in children with right atrial thrombi and probability of pulmonary microembolism or embolism. As the incidence of right atrial thrombi is highly associated with the catheter tip position in the right atrium, in contrast to their positioning in the superior vena cava or in its junction with the right atrium, the authors recommend that special attention and effort should be given to placing of the catheter tip in the superior vena cava or in its junction with the right atrium avoiding the right atrium during the implantation procedure. The surgical right atrium thrombus removal in patients with no clot dissolution despite systemic thrombolytic treatment underscores the importance of surgical therapy in treating this life-threatening complication of indwelling catheters.