Abstract
We report a case of a 60-year-old woman with a cutaneous primitive neuroectodermal tumor (PNET) on her left knee. The patient noticed a subcutaneous nodule on her left knee since April 2009, and that it had been gradually increasing in size for 4 months. Hematoxylin and eosin staining of the specimen showed that the tumor was composed of uniform small round cells with atypical nuclei. The tumor cells showed positive reactions with CD99, vimentin, CD56, and synaptophysin. Chromosomal fluorescence in situ hybridization (FISH) from the tumor cells showed translocation of chromosome No. 22 q12. Therefore, the tumor was diagnosed as PNET. In Japan, only 9 cases including our case have been reported.[Skin Cancer (Japan) 2010 ; 25 : 343-347]
