[Partially differentiated cystic nephroblastoma]

The case of a patient with a cystic partially differentiated nephroblastoma (CPDN) is reported. Careful histological study is essential to distinguish CPDN and other types of multicystic kidneys (specially cystic nephroma or multilocular cyst of the kidney). Because of the rare potential for aggressive behavior of this tumor, nephrectomy alone is the therapy of choice. However, its relationship with Wilm's tumor is an indication for a regular clinical follow up.