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Int J Clin Exp Pathol 2013;6(4):724-728

Case Report
Multiple cytokeratin-negative malignant tumors composed only of rhabdoid cells in the
renal pelvis: a sarcomatoid urothelial carcino-ma?

Tadashi Terada

Department of Pathology, Shizuoka City Shimizu Hospital, Shizuoka, Japan

Received September 21, 2012; Accepted February 3, 2013; Epub March 15, 2013; Published April 1, 2013

Abstract: The author presents a unique case of multiple cytokeratin-negative malignant tumors consisting only of rhabdoid cells in the renal
pelvis. A 54-year-old man complained of hematuria. A transurethral endoscopic examination revealed multiple papillary tumors, and tran-
surethral resection of the bladder tumors was performed. Pathologically, they were ordinary papillary urothelial transitional cell carcinomas.
Imaging modalities revealed multiple tumors of the right renal pelvis, and nephrectomy was performed. Grossly, three polypoid tumors
measuring 2-4 cm were present in the pelvis. Histologically, they were composed only of malignant cells with rhabdoid features. There were no
elements of transitional cell carcinoma. Immunohistochemically, the pelvic tumors were positive for vimentin and Ki-67 antigen (labeling=40%).
They were negative for pancytokeratins (AE1/3, CAM5.2, KL-1 and polyclonal wide), 34βE12, cytokeratin (CK) 5/6, CK7, CK8, CK14, CK18,
CK19, CK20, melanosome, EMA, CEA, desmin, S100 protein, α-smooth muscle actin, myoglobin, myogenin, CD34, p53 protein, p63, CD3,
CD20, CD30, CD45, CD45RO, chromograin, synaptophysin, CD56, CD68, and KIT. NSE and PDGFRA were focally present, but this appeared
non-specific. Namely, the pelvic tumors expressed only vimentin. The author speculates that the pelvic multiple malignant “rhabdoid” tumors
are not sarcomas but urothelial “rhabdoid” carcinoma with complete loss of CKs. (IJCEP1209018)

Keywords: Rhabdoid tumor, urothelial carcinoma, renal pelvis, immunohistochemistry

Address correspondence to: Dr. Tadashi Terada, Department of Pathology, Shizuoka City Shimizu Hospital, Miyakami 1231 Shimizu-Ku, Shi-
zuoka 424-8636, Japan. Tel: 81-54-336-1111; Fax: 81-54-336-1315; E-mail: piyo0111jp@yahoo.co.jp