Synovial Sarcoma of the Kidney: A Clinicopathologic, Immunohistochemical, and Molecular Genetic Study of 16 CasesSchoolmeester, John Kenneth MD; Cheville, John C. MD; Folpe, Andrew L. MDAmerican Journal of Surgical Pathology: January 2014 - Volume 38 - Issue 1 - p 60–65 doi: 10.1097/PAS.0b013e31829b2d0d Original Articles Abstract Author Information Abstract We report the clinicopathologic and immunohistochemical features of 16 cases of genetically confirmed primary synovial sarcoma of the kidney. The cases occurred in 9 men and 7 women ranging in age from 17 to 78 years (mean, 46 y). The tumors were grossly large, solid, and variably cystic (2.2 to 19.0 cm; mean 8.6 cm). Microscopically, all tumors were of the monophasic type and diffusely immunoreactive for TLE1 and BCL-2. Focal pankeratin positivity was found in just under half. Ten cases carried an SS18-SSX2 fusion transcript, and 5 cases showed an SS18-SSX1 transcript by reverse transcription polymerase chain reaction. The remaining case demonstrated SS18 rearrangement by fluorescence in situ hybridization. Clinical follow-up information was available for 12 patients (range, 1 to 77 mo; mean, 32.5 mo). Fourteen patients underwent radical nephrectomy, and 3 patients had lung metastases at presentation. Six patients died of disease within 1 to 58 months (mean, 31 mo) of their diagnosis. Five patients were alive without evidence of disease 12 to 77 months (mean, 39 mos) after surgery. A single patient was alive with metastases to the spine 11 months after surgery. We conclude that renal synovial sarcoma is an aggressive tumor, with adverse patient outcome in >50% of cases. Synovial sarcoma must be distinguished from morphologically similar lesions of the kidney. Author Information Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article. Correspondence: Andrew L. Folpe, MD, Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First St SE, Rochester, MN 55905 (e-mail: email@example.com). © 2014 by Lippincott Williams & Wilkins.