We looked at the tumor together with our pediatric pathologist, Prof. Elisabeth Bruder. We see an epitheloid tumor with some rhabdoid features. A non-semninomatous germ cell tumor is one possible DD, yet the aptient's age and he lack of (at least not stated) of a testicular tumor are not typical. DDs would be rhabdomyosarcoma, renal cell carcinoma with rhabdomyosarcomatous compound and a rhabdoid tumor. We suggest some basic stainings: at least PAS, silver impregnation, cytokeratin (pan), OCT2, CD30, desmin, CD56, CD34, EMA; if possible INI1, MyoD1, myogenin, CDX2, PLAP, CD117, CAIX, CD10, AFP. We also suggest correation with the imaging (US or CT) - testicles? kidneys? and with the lab - LDH? AFP? HCG? etc.