Decoding the 'embryonic' nature of embryonal rhabdomyosarcoma.

Embryonal rhabdomyosarcoma is one of the major defined histologic variants of rhabdomyosarcoma that is mainly reported in children. The histologic appearance of this neoplastic entity recapitulates normal myogenesis. The tumor cells variably exhibit the different cellular phases of myogenesis ranging from undifferentiated mesenchymal cells to elongated myoblasts, multinucleated myotubes and differentiated muscle fibers. The carefully orchestrated embryonic signaling pathways that are involved in myogenesis, conceivably also result in the genesis of rhabdomyosarcoma; albeit as a corollary to an imbalance. We have attempted to review the pathogenesis of embryonal rhabdomyosarcoma in an endeavor to understand better, how closely it is linked to normal myogenesis in terms of its molecular dynamics and histologic presentation.