BACKGROUND: Right atrial involvement in children with Wilms' tumor (nephroblastoma) is a very rare phenomenon. CASE REPORT: The authors present four children with nephroblastoma, in whom the tumor involved the inferior vena cava and the right atrium. In two children the intracardiac tumor extension was asymptomatic, while the other two had Budd-Chiari syndrome. Therapeutic management included initial three-drug chemotherapy in three patients, and primary tumor excision in one child, since the venous involvement had been not diagnosed. In each child, the therapeutic strategy was individualized and tailored to the course of the disease. Two patients were cured. The child with bilateral Wilms' tumor died due to disease progression. Another child died suddenly at home in the course of an intermission between consecutive cycles of successful chemotherapy. CONCLUSIONS: The extension of Wilms' tumor to the great vessels and the right atrium indirectly affects the final outcome. Preoperative chemotherapy in children with Wilms' tumor invading the inferior vena cava and the right atrium is the method of choice. The extent of surgery depends on the preliminary chemotherapy results.

Keywords: Heart Neoplasms - therapy