A malignant mesenchymal neoplasm of the prostate. It is characterized by the presence of skeletal muscle exhibiting embryonic features. The disease is Monarch Disease Ontology term MONDO_0002574 (prostate embryonal rhabdomyosarcoma). Also known as: embryonal rhabdomyosarcoma (disease) of prostate gland, embryonal rhabdomyosarcoma of prostate, embryonal rhabdomyosarcoma of the prostate, prostate gland embryonal rhabdomyosarcoma (disease).