Mondo Description A poorly circumscribed morphologic variant of rhabdomyosarcoma. It is characterized by the presence of primitive skeletal muscle differentiation in any stage of myogenesis.

Uniprot Description A form of rhabdomyosarcoma, a highly malignant tumor of striated muscle derived from primitive mesenchymal cells and exhibiting differentiation along rhabdomyoblastic lines. Rhabdomyosarcoma is one of the most frequently occurring soft tissue sarcomas and the most common in children. It occurs in four forms: alveolar, pleomorphic, embryonal and botryoidal rhabdomyosarcomas.

Disease Ontology Description A rhabdomyosarcoma wherein the mesenchymally-derived malignant cells resemble the primitive developing skeletal muscle of the embryo; it occurs most often in the head and neck area or in the genital or urinary organs.