The immunohistochemical analysis was positive for the antigens: MyoD1, myogenin, desmin, and Ki67 (100% positivity in neoplastic cells), allowing the identification of the tumour as an eRMS.
In this study, distinct methylation alterations were identified in the 5' flanking region of the MyoD1 gene from the two major subtypes, ie, alveolar and embryonal rhabdomyosarcoma.
A recurrent neomorphic mutation in MYOD1 defines a clinically aggressive subset of embryonal rhabdomyosarcoma associated with PI3K-AKT pathway mutations.
Immunohistochemical stains were positive for vimentin, CD99, myogenin, and MyoD1 consistent with a diagnosis of embryonal rhabdomyosarcoma, botryoid subtype.