Online Articles: Case ReportsCollision Tumor of Urothelial Cell Carcinoma and Clear Cell Renal Cell Carcinoma: A Case Report and Review of the Contemporary LiteratureGriffin, Jon FRCPath; Tahir, Fawzia FRCPathAuthor Information Department of Histopathology, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom The authors declare no conflict of interest. Reprints: Jon Griffin, FRCPath, Department of Histopathology, Royal Hallamshire Hospital, Sheffield Teaching Hospitals NHS Foundation Trust, Glossop Road, Sheffield, S10 2JF, United Kingdom (e-mail: [email protected]). Applied Immunohistochemistry & Molecular Morphology: October 2020 - Volume 28 - Issue 9 - p e82-e86 doi: 10.1097/PAI.0000000000000728 Buy Metrics Abstract We present a case of synchronous renal cell carcinoma and urothelial carcinoma. Our case was a true collision tumor and both components were high grade. Metastasis to the adrenal gland by the urothelial carcinoma was observed. The morphologic impression was confirmed with GATA3 expression by the urothelial carcinoma component and PAX8 expression by the renal cell carcinoma component. We have reviewed the contemporary literature of this unusual dual diagnosis. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.