In a review of 111 cases of MRT of kidney by the National Wilms’ Tumor Study (Weeks, 1989) the median age at diagnosis was 11 months (range 0 – 106 months) and the male: female ratio was 1.5:1. Treatment for MRT of kidney is often similar to that for Wilms’ tumor (MRT starting in the brain or other non-renal sites have different treatments). A common cytogenetic feature of MRT is deletion of material from chromosome 22q11.2 including the SMARCB1 (SNF5/INI1) gene.