ABSTRACT

Primary primitive neuroectodermal tumor of the kidney is a rare and aggressive tumor. Its distinction from other primary renal tumors is clinically important due to different therapeutic management. A 44-year-old man was admitted to the hospital with left flank pain and hematuria. In computerized tomography, a mass in left kidney was detected and nephrectomy was performed. Microscopically the tumor was composed of small round cells. Immunohistochemically, diffuse strong positivity for CD 99 (MIC2) and NSE, and focal positivity for Wilms tumor 1 were determined in the tumor cells. In this report, a rare renal primary primitive neuroectodermal tumor showing both CD99 and Wilms tumor 1 expression is presented.