en Radiation Biology Radiation Biology مطالعه موردي Case Report Desmoplastic small round cell tumor is a rare malignant tumor that occurs primarily in young males. Here, a case of small round cell tumor in an adult male successfully treated with a curative concurrent chemoradiotherapy is presented. A 58-year-old man had an intrapelvic tumor. Surgical resection was attempted, but the tumor was unresectable. Needle biopsy was performed and the diagnosis was suggested to be desmoplastic small round cell tumor. Concurrent chemoradiotherapy was performed, and a complete response was obtained. This patient has been alive for 8 years after treatment with no evidence of disease. Concurrent chemoradiotherapy appears to be a useful treatment choice for unresectable desmoplastic small round cell tumor. <span style="font-weight: bold">Iran. J. Radiat. Res., 2011 9(3): 201-205</span> desmoplastic small round cell tumor, concurrent chemoradiotherapy, retroperitoneum 201 205 http://ijrr.com/browse.php?a_code=A-10-1-403&slc_lang=en&sid=1 J.I. Saitoh junsaito@gunma-u.ac.jp 790031947532846002412 790031947532846002412 Yes H. Ishikawa 790031947532846002413 790031947532846002413 No T. Ebara 790031947532846002414 790031947532846002414 No H. Katoh 790031947532846002415 790031947532846002415 No T. Ohno 790031947532846002416 790031947532846002416 No T. Takahashi 790031947532846002417 790031947532846002417 No T. Akimoto 790031947532846002418 790031947532846002418 No T. Nakajima 790031947532846002419 790031947532846002419 No T. Nakano 790031947532846002420 790031947532846002420 No