CYTOGENIC ABNORMALITIES OF SMALL ROUND-CELL TUMORS

Between 1987 and 1991, cytogenetic studies were carried out on small r ound cell tumours of 68 patients from the Northern Health Region of En gland. Clonal chromosome abnormalities were found in 30, comprising 15 neuroblastomas, 7 Ewing's tumours, 7 rhabdomyosarcomas, and 1 granula r cell tumour. Characteristic rearrangements were found in five cases of Ewing's tumour [all with translocation t(11;22) (q24;q12)] and in f our cases of rhabdomyosarcoma [all with evidence of translocation t(2; 13) (q35-37;q14)]. In one case of Ewing's tumour and three of rhabdomy osarcoma, the cytogenetic findings were important in diagnosis. Within the neuroblastomas, examples were found of hyperdiploidy, lp rearrang ements, double minute chromosomes, and homogeneously staining regions, but too few cases were available for prognostic associations to be as sessed. Our findings confirm the diagnostic importance of chromosome a bnormalities in small round cell tumours and indicate that cytogenetic analysis should be an intrinsic part of the initial investigations of all patients with such tumours. (C) 1994 Wiley-Liss, Inc.