Embryonal rhabdomyosarcoma with only numerical chromosome changes. Case report and review of the literature.

An embryonal rhabdomyosarcoma, presenting as a retroperitoneal mass in a 15-year-old girl, is reported. The histological and immunohistochemical picture was typical, except for the presence of focal chondroid differentiation. Interestingly, expression of the "muscle markers" desmin and alpha-sarcomeric actin was present in the latter areas. Cytogenetic analysis showed a hyperdiploid karyotype without structural chromosome changes. The pertinent literature on the subject is reviewed. Hyperdiploidy of the clonal type seems to occur frequently, but no characteristic karyotype is so far emerging.