Cytogenetic-clinicopathologic correlations in rhabdomyosarcoma: a report of five cases

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children y ounger than the age of 15 years. Histologically, RMS can be subdivided into two major subtypes; embryonal (E-RMS) and alveolar (A-RMS) rhabdomyosarcom a, with E-RMS being the more common. Although cytogenetic and molecular gen etic findings have been reported extensively for RMS, clinicopathologic-gen etic correlations among these tumors have not been reported in detail. In t his report, we correlate the cytogenetic findings, including fluorescence i n situ hybridization and spectral karyotyping, with pathologic findings and outcome for five RMS, including two A-RMS, one E-RMS, one botryoid RMS, an d one anaplastic nonclassified RMS (N-RMS). The findings in A-RMS and E-RMS generally were consistent with previous reports; however, gain of chromoso me 7 in A-RMS and gain of chromosome 9 segments in E-RMS observed here: hav e seldom been reported in the literature. Importantly, the botryoid RMS had a cytogenetic profile similar to other types of E-RMS. An add(11)(q21) obs erved in this tumor, together with a t(8;11)(q12-13; q21) reported previous ly, indicates that 11q21 rearrangements may be nonrandomly related to botry oid RMS. In addition, the N-RMS expressed a cytogenetic pattern similar to that observed in E-RMS, thus providing genetic evidence that anaplastic N-R MS is a variant of E-RMS. Finally, these cases provide cogent evidence for the diagnostic and prognostic significance of the pathologic-genetic classi fication of RMS. (C) 2001 Elsevier Science Inc. All rights reserved.