You have accessJournal of UrologyKidney Cancer: Evaluation and Staging III1 Apr 2015MP50-17 INCIDENCE OF HYBRID TUMORS FOUND IN EXCISED RENAL MASSES: A MULTI-INSTITUTIONAL ANALYSIS David Fumo, Khaled Shahrour, Ravi Munver, and Samay Jain David FumoDavid Fumo More articles by this author , Khaled ShahrourKhaled Shahrour More articles by this author , Ravi MunverRavi Munver More articles by this author , and Samay JainSamay Jain More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.2928AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The use of renal biopsy has gained popularity as an adjunct in the work up of renal masses, particularly masses ≤ 4cm suspicious for renal cell carcinoma (RCC). Our present study attempts to quantify the prevalence of tumors that contain more than one histology as a means of determining the potential accuracy of renal biopsy. METHODS In this IRB approved, multi-institutional study, a retrospective review of renal masses removed for RCC from January 1998- December 2013 was performed. Patients and masses were included in the study if information pertaining to demographics and pathologic stage, mass size, and histology were present. Tumors were considered to be hybrid if more than one distinct histology was reported in the final pathology. An independent pathology review was performed on 39 tumors from UTMC, of which 39% were hybrid and 41% were single histology. Statistical analyses were completed with paired T-tests and Chi Squared analysis, where appropriate. RESULTS A total of 447 tumors were included in the analysis, summarized in Table 1. After completion of pathology review, 39 tumors were found to be hybrid. pT1a masses accounted for 17 (43.6%) hybrid tumors, the majority of which (13/17) were a combination of clear cell and papillary cell RCC. Four hybrid tumors showed a combination of malignant and benign histology. Two of these were pT1a, and two were pT1b. Hybrid tumors made up 8.7% of all masses, with benign/malignant combinations accounting for 0.9% of all masses. An independent pathology review of 39 masses demonstrated a 64% concordance rate (14 discordant findings). Four of these 14 discordances involved a discrepancy between Oncocytoma and Chromophobe histologies. The pathologist suggested that immunohistochemical staining would have been beneficial in the initial diagnosis, which was not a common practice at that time. CONCLUSIONS Based on the low incidence of combined benign and malignant hybrid tumors, renal biopsy can be considered an accurate determinant of tumor histology. However, care should be taken in differentiating chromophobe from oncocytoma and should include the use of specialty staining. Larger studies are needed to confirm our findings. Table 1. Hybrid Histology Single Histology P Value Total Masses 39 408 Mean Size (cm) 5.2 5.2 .63 Mean Age 63.2 61.8 .65 Male 31 243 pT1a 17 169 .74 pT1b 6 112 .12 pT2a 2 27 1 pT2b 2 16 .66 pT3a 7 51 .31 pT3b 3 28 .74 pT3c 1 2 pT4 1 3 Mixed Histology Clear Papillary 24 Clear Chromophobe 5 Papillary Other Malignant 5 Undifferentiated CDC 1 Oncocytic Chromophobe 2 Oncocytic Papillary Patient Demographics, tumor stages, and hybrid tumor histology © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e617-e618 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information David Fumo More articles by this author Khaled Shahrour More articles by this author Ravi Munver More articles by this author Samay Jain More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...