A combined cytogenetic and molecular approach to diagnosis in a case of desmoplastic small round cell tumor with a complex translocation (11;22;21).

Desmoplastic small round cell tumor (DSRCT) has recently been described as a discrete tumor entity. It is distinguished from other small round cell tumors by its prominent desmoplastic quality, its preponderance in adolescent males, its almost exclusive intraabdominal location, a multi-immunophenotypic profile, and its aggressive nature. Diagnosis on histology alone is not always unequivocal. A recurrent t(11;22)(p13;q12) translocation has recently been described in this tumor, and a chimeric RNA fusion product formed from the WT1 and EWS genes is detectable by reverse transcriptase-polymerase chain reaction (RT-PCR). We describe the use of a multi-faceted approach using conventional G-banding, fluorescence in situ hybridization (FISH) and RT-PCR to assist the diagnosis of a case of DSRCT with a complex variant t(11;22;21)(p13;q12;q22.1) translocation and demonstrate the value of a combined approach to genetic investigation of solid tumors.