MALIGNANT RHABDOID TUMOR OF THE KIDNEY - INVOLVEMENT OF CHROMOSOME-22

Cytogenetic and molecular studies have demonstrated that involvement o f 22q is a non-random finding in malignant rhabdoid tumors (MRTs) of t he brain. We present an MRT of the kidney with the karyotype 47,XY,+i( 1)(q10), der(8)t(8;22)(q12;q11.2),der(22)t(8;22)(q23 or q24.1;q11.2). This unbalanced reciprocal translocation was confirmed by fluorescence in situ hybridization (FISH) with chromosome-specific paints for chro mosomes 8 and 22. Molecular analysis demonstrated a partial deletion o f 22q in the BCR region at q11.2, strengthening the suspicion that thi s is a critical region for the initiation or progression of these high ly malignant neoplasms. Establishing non-random cytogenetic changes in MRTs arising from the kidney may be of value in distinguishing these rare, but often fatal tumors from other renal neoplasms that mimick th em histologically. The similarity in cytogenetic and molecular abnorma lities between renal and extra-renal MRTs argues against the concept t hat extra-renal MRTs are only representative of a rhabdoid phenotype, rather than being true rhabdoid tumors. (C) 1994 Wiley-Liss, Inc.