Late recurrence of Wilms tumor.

Three patients with Wilms tumors recurring after nine years in an organized abdominal hematoma, after ten years in the lung, and after eleven years in the central nervous system, respectively, are presented. It is proposed that the nephroblastoma cells have survived in a latent or a very slowly growing state. The reactivation mechanisms are briefly discussed. A review of the literature indicates a rate of recurrence of nonmetastasizing Wilms tumors later than 24 months of 1.4--3.9%.