Another case was originally diagnosed as T-lymphoblastic leukemia/lymphoma based on erroneous TdT interpretation and CD56 positivity in the tumor cells, but was reclassified as a rhabdomyosarcoma as a repeat TdT stain in our laboratory was negative, and the tumor cells were diffusely and strongly positive for muscle markers. The gene discussed is NCAM1; the disease is rhabdomyosarcoma.