This is a post-chemotherapy specimen of a clear cell sarcoma of the kidney (CCSK). The tumor has fleshy, pink-tan cut surface with areas of hemorrhage and necrosis. Unlike Wilms tumor, there are no cases of familial or syndrome-associated cases of CCSK. Most cases of CCSK present with a flank mass. Some patients present with pathologic fractures resulting from metastases to the bone. Due to this tendency, it has previously been referred to as the bone-metastasizing renal tumor of childhood. Image courtesy of Dr. Jean-Christophe Fournet, Paris, France; humpath.com; Used with permission.