MP40-06 MOST CYTOGENETICALLY PROVEN RENAL ONCOCYTOMAS AND CHROMOPHOBE CARCINOMAS CAN BE DIFFERENTIATED BY ROUTINE H&E AND CYTOKERATIN 7 STAINS ALONE (2014)

You have accessJournal of UrologyKidney Cancer; Evaluation/Staging IV1 Apr 2014MP40-06 MOST CYTOGENETICALLY PROVEN RENAL ONCOCYTOMAS AND CHROMOPHOBE CARCINOMAS CAN BE DIFFERENTIATED BY ROUTINE H&E AND CYTOKERATIN 7 STAINS ALONE Reza Mehrazin, Essel Dulaimi, Hussam Nash, Alexander Kutikov, Jeffrey J. Tomaszewski, Jianming Pei, Marc C. Smaldone, Philip Abbosh, Timothy Ito, Joseph R. Testa, Tahseen Al-Saleem, and Robert G. Uzzo Reza MehrazinReza Mehrazin More articles by this author , Essel DulaimiEssel Dulaimi More articles by this author , Hussam NashHussam Nash More articles by this author , Alexander KutikovAlexander Kutikov More articles by this author , Jeffrey J. TomaszewskiJeffrey J. Tomaszewski More articles by this author , Jianming PeiJianming Pei More articles by this author , Marc C. SmaldoneMarc C. Smaldone More articles by this author , Philip AbboshPhilip Abbosh More articles by this author , Timothy ItoTimothy Ito More articles by this author , Joseph R. TestaJoseph R. Testa More articles by this author , Tahseen Al-SaleemTahseen Al-Saleem More articles by this author , and Robert G. UzzoRobert G. Uzzo More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.1341AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail Introduction and Objectives Even though the role of percutaneous renal mass biopsy has been expanding in urologic practice, descriptive histology (e.g., oncocytic lesion) and overlapping morphologic characteristics of chromophobe renal cell carcinoma (chRCC) and oncocytoma remain problematic. Cytokratin7 (CK7) immunohistochemistry staining is often used to differentiate between the two. Using a combination of routine hematoxylin & eosin (H&E) staining, CK7, and cytogenetic analysis, we sought to establish a consistent diagnostic approach. Methods Our prospectively maintained institutional renal tumor registry was reviewed to identify originally classified chRCC and oncocytomas. Tumors that did not have cytogenetic analysis (conventional or cytogenomic microarray analysis) were excluded from analysis. All cases were stained by CK7 and evaluated independently by two uropathologists. Findings were then correlated with results from the cytogenetic analysis. Results Out of 116 chRCCs and 164 oncocytomas, 29 and 32 had cytogenetic analysis, respectively. Both pathologists noted that cytogenetically classical chRCC’s had sheets of cells positive for CK7 staining of 40-100% (mean 81%; median 100%). On the other hand, CK7 stained only rare cells within oncocytomas (mean 2%; median 1%) (Graph). H&E, CK7, and cytogenetic analysis (i.e., loss of chromosome 1 in oncocytoma; multiple chromosome losses involving 1, 2, 6, 10, 13 and 21 in chRCC) were matched for 83% (24) and 84% (27) of chRCC and oncocytoma tumors, respectively. Ten tumors (16%) were considered as atypical oncocytic neoplasms with atypical morphological and CK7 expression pattern. Four of the atypical cases were considered “hybrid" oncocytomas/chromophobe carcinoma based on all three criteria. In another five cases, the H&E and CK7 matched, but the cytogenetic analysis did not confirm the diagnosis. One of the tumors showed pronounced papillary oncocytic architecture and was labeled as a papillary oncocytic neoplasm. Conclusions The morphological evaluation combined with strong, diffuse CK7 expression, or the presence of sheets of CK7 cells is a reliable diagnostic tool to differentiate chromophobe renal cell carcinoma from oncocytoma. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e436 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Reza Mehrazin More articles by this author Essel Dulaimi More articles by this author Hussam Nash More articles by this author Alexander Kutikov More articles by this author Jeffrey J. Tomaszewski More articles by this author Jianming Pei More articles by this author Marc C. Smaldone More articles by this author Philip Abbosh More articles by this author Timothy Ito More articles by this author Joseph R. Testa More articles by this author Tahseen Al-Saleem More articles by this author Robert G. Uzzo More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...