In our case, the diffuse cytoplasmic expression of CD163 and NKI-C3, and negative staining for schwannian markers, S100/SOX10, or myogenic markers, desmin/caldesmon/myogenin/MyoD1, confirmed the histiocytic nature of the lesional cells and essentially excluded the diagnosis of granular cell tumor and rhabdomyoma. The gene discussed is MYOG; the disease is rhabdomyoma.