Spindle cell rhabdomyosarcoma: histologic variant of embryonal rhabdomyosarcoma with association to favorable prognosis.

Abstract

Rhabdomyosarcoma (RMS) is the most important malignant soft tissue tumor of childhood (Enzinger and Weiss 1988). Following the first detailed description of an RMS of the skeletal muscles by Stout (1946), this entity was subdivided by histologic criteria into embryonal (Stobbe and Dargeon 1950), alveolar (Riopelle and Theriault 1956), botryoid (Horn et al. 1955), and pleomorphic variants (Horn and Enterline 1958). Later it could be shown that the botryoid RMS is a subtype of embryonal RMS. In clinical studies, it has been demonstrated that the distinction of these subtypes of RMS has an influence on prognosis in children (NEWTON et al. 1988). However, this classification of RMS into four subtypes does not relate to prognosis in all patients. Subsequently, the “solid alveolar RMS” was excluded from embryonal RMS (Tsokos et al. 1984). This tumor type has the cytology of typical alveolar RMS but does not form the regressive alveolar spaces. Prognosis is similar to that of typical alveolar RMS (see chapter by D. Harms, this volume). Recently two independent studies were published concerning a subtype of embryonal RMS which is exclusively composed of spindle cells (Cavazzana et al. 1992; Leuschner et al. 1993).KeywordsSpindle CellEmbryonal RhabdomyosarcomaPloidy AnalysisAlveolar RhabdomyosarcomaConventional HistologyThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.