Malignant Extra-Renal Rhabdoid Tumor: Cytokeratin
Malignant extrarenal rhabdoid tumor frequently shows co-expression of epithelial, mesenchymal, and neural markers. The tumor cells are usually positive for vimentin, cytokeratin (focal positivity in this image), and EMA. Markers such as muscle specific actin, smooth muscle actin, CD99, CD57, synaptophysin, and S-100 protein are occasionally expressed. This image is from rhabdoid tumor of kidney; renal and extrarenal rhabdoid tumors have similar immunohistochemical profile. Image courtesy of Dr. Jean-Christophe Fournet, Paris, France; humpath.com; Used with permission.