Rhabdomyoblast
A rhabdomyoblast is a cell type which is essential to the diagnosis of a rhabdomyosarcoma. A rhabdomyoblast found histologically is considered diagnostic for embryonal, alveolar, and pleomorphic rhabdomyosarcomas. Histology will show an elongated or round cell, exhibiting an embryonic morphology. Occasionally cells will exhibit cross striations by light microscopy, reflecting sarcomere formation and advancement of differentiation. This differentiated phenotype increases following chemotherapy and radiotherapy.