[Successful therapy of local recurrence of congenital mesoblastic nephroma].

A 3 1/2 month old girl was found to have a large abdominal tumor originating in the upper pole of the right kidney. At laparotomy the tumor had infiltrated the perirenal fat, the right lobe of the liver and the diaphragm. Partial nephrectomy was performed and the tumor was completely resected. However, an adequate safety margin could not be achieved. Histology showed a congenital mesoblastic nephroma of the cellular subtype. Postoperatively no chemotherapy was considered necessary. 11 months after diagnosis the patient had an extensive local recurrence with infiltration of the perirenal fat, mesenterium and colon. Complete resection could not be achieved and the tumor was classified as stage III. There was a striking morphological change from spindle cells in the initial tumor to malignant round cells in the relapse specimen. The patient was treated with Vincristine, Actinomycin-D and Adriblastin. Radiotherapy was not given. 38 months after relapse the patient is free of disease and developing normally. Our patient obviously had an aggressive variant of CMN. The significance of the potentially aggressive variant of CMN, atypical mesoblastic nephroma, is discussed and possibilities are suggested for management.