Figure 1.

(a) Primary renal cell carcinoma (clear cell type) in the kidney. The tumor (t) is sharply demarcated from the renal parenchyma (k). The tumor consists of sheets of large epithelial cells with an optically empty cytoplasm and sharp cell borders (inset). (original magnification 25x and 200x (inset); Hematoxylin Eosin stain), (b) Metastasis of clear cell carcinoma in the oscalcaneum. Note the similar cell type in metastasis and primary tumor (original magnification 200x; Hematoxylin Eosin stain). (c) Ovarian metastasis of clear cell carcinoma. Note the similar cell type in metastasis and primary tumor (original magnification 200x; Hematoxylin Eosin stain). (d) Metastasis of clear cell carcinoma in the gallbladder. The tumor (t) is located deep in the cholecystic wall (m: mucosa) (original magnification 25x; Hematoxylin Eosin stain). Inset: the tumor cells show the typical membranous staining pattern for CD10, consistent with the immunophenotype of a clear cell RCC (original magnification 200x; immunohistochemical CD10 stain).