Sclerosing Epithelioid Fibrosarcoma of the Kidney

Han Yung Choi, Nam Sung Kwon, Seung Joon Lee, Dong Kil Lee, Kwanjin Park, Chong Wook Lee, Moon Ki Jo From the Department of Urology, Korea Cancer Center Hospital, Seoul, Korea Sclerosing epithelioid fibrosarcoma (SEF) is an uncommon tumor of the deep soft tissue. It was first described in 1995 by Meis-Kindblom et al. Histologically, this tumor is characterized by uniform, small, round to ovoid epithelioid cells with clear cytoplasm, and the cells are arranged in distinct nests and cords. On immunohistochemistry, the most consistently positive marker is vimentin, although other antigens (cytokeratin, epithelial membrane antigen, S100 protein and neuron specific enolase) have been recorded as being inconsistently positive. We report here on a case of a 46-year-old woman who presented with back pain. The radiologic findings revealed a right renal mass and multiple bone metastases. The patient underwent radical nephrectomy and the pathologic finding was primary SEF of the kidney. (Korean J Urol 2007;48:986-989)