Treatment Strategy for Pediatric Paratesticular Rhabdomyosarcoma Based on Chimeric Gene Assessment

Rhabdomyosarcoma (RMS), a malignant tumor of the soft tissue, occurs in two major subtypes: embryonal and alveolar. A majority of pediatric RMS cases involve the embryonal type and occur in the soft tissues of the head and neck or the urogenital organs, which contain paratesticular tissues. We report herein two cases of pediatric paratesticular RMS. One case was embryonal, whereas the other case was alveolar; the latter exhibited PAX7-FOXO1 gene chimerism and rapid progression. Notably, this is the first report of pediatric paratesticular pure-type alveolar RMS in Japan.