Nickan Research Institute Immunopathologia Persa 2423-8015 2 2 2016 07 01 Proximal type of epithelioid sarcoma presented as huge retroperitoneal mass in an old man; a case report and review of literature e23 EN Somaia A Saad El-Din Marwa M Shakweer Journal Article 2016 06 06 2016 08 03 Epithelioid sarcoma (ES) is a tumor of unknown origin as classified by the World Health Organization (WHO). It is a rare subcutaneous or deep dermal soft tissue sarcoma that was first described by Enzinger in 1970. Then, Guillou et al described a different proximal/axial deep seated type that frequently occurs in older patients. We present a case of 61-year-old male with a huge retroperitoneal mass that proved to be ES proximal type after clinical examination and investigations were done and correlated with the histopathological features including H&E stained sections and panel of immunohistochemical markers.