Primary peripheral primitive neuroectodermal tumor/Ewing's tumor of the testis in a 46-year-old man-differential diagnosis and review of the literature.

Peripheral primitive neuroectodermal tumor/Ewing's tumors are rare bone and soft tissue malignancies with a highly aggressive clinical course and early metastases occurring at multiple peripheral sites. Here, we present for the first time a case of a 46-year-old man with a primary peripheral primitive neuroectodermal tumor/Ewing's tumor of the testis. The diagnosis of peripheral primitive neuroectodermal tumor/Ewing's tumor was established by histology, immunohistochemistry, and molecular pathology. The tumor revealed a rapid progress in 2 months' time. Therefore, the patient was included in the EURO-E.W.I.N.G.99 study and was placed on chemotherapy. However, the tumor progressed during ongoing therapy, and the patient died in March 2008. In conclusion, though being reported here for the first time, peripheral primitive neuroectodermal tumor/Ewing's tumors should be considered in the differential diagnosis of blue round cell tumors of the testis. A rapid and correct diagnosis of this entity is crucial for fast and accurate therapy, which is stressed by the fatal case presented here.