Teratoid Wilms' tumor: Report of a unilateral case

Teratoid Wilms' tumor is a rare histologic variant of the classical Wilms' tumor, containing predominantly heterologous tissues (adipose, glial, muscle, cartilage, or bone). This report presents the case of a teratoid Wilms' tumor in a 4-year-old girl. The mass, which originated from the right kidney, was very large and encased the inferior vena cava and renal vessels. The child did not respond to chemo- or radiotherapy and underwent operation. Despite the enormous dimensions of the tumor and the involvement of the inferior vena cava, a radical excision was obtained, and now the child is well 32 months after surgery. The behavior of this kind of tumor usually is not aggressive, and the outcome is good. Surgery should be the treatment of choice, because the efficacy of chemotherapy and radiotherapy is probably reduced by the high amount of differentiated and mature tissue which characterizes this neoplasm.