First, Myogenin positivity was focal, rather than diffuse, and lacked the supporting morphological features of rhabdomyosarcoma such as strap cells, eosinophilic cytoplasm, and cross-striations. Second, the overall architecture and cellular composition of the tumor, including the inflammatory background, myxoid zones, and the presence of bizarre and vacuolated tumor cells, were more in keeping with MIFS. Third, CD68 expression, a marker often expressed in MIFS and suggestive of histiocytic or fibroblastic differentiation, was also positive in tumor cells. The gene discussed is MYOG; the disease is rhabdomyosarcoma.