Diagnostic Criteria for Oncocytic Renal Neoplasms: A Survey of Urologic Pathologists

• Published in: Human pathology Vol. 63; pp. 149 - 156
• Main Authors: Williamson, Sean R, MD, Gadde, Ramya, MD, Trpkov, Kiril, MD, Hirsch, Michelle S., MD, PhD, Srigley, John R, MD, Reuter, Victor E, MD, Cheng, Liang, MD, Priya Kunju, L, MD, Barod, Ravi, MD, Rogers, Craig G, MD, Delahunt, Brett, MD, Hes, Ondrej, MD, Eble, John N, MD, Zhou, Ming, MD, PhD, McKenney, Jesse K, MD, Martignoni, Guido, MD, Fleming, Stewart, MD, Grignon, David J, MD, Moch, Holger, MD, Gupta, Nilesh S, MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-05-2017; Elsevier Limited
• Subjects: Adenoma, Oxyphilic - chemistry; Adenoma, Oxyphilic - genetics; Adenoma, Oxyphilic - pathology; Biomarkers, Tumor - analysis; Biomarkers, Tumor - genetics; Biopsy; Cancer; Carcinoma, Renal Cell - chemistry; Carcinoma, Renal Cell - genetics; Carcinoma, Renal Cell - pathology; Cell Proliferation; Chromophobe renal cell carcinoma; Diagnosis, Differential; Diagnostic criteria; Health Care Surveys; Health risk assessment; Humans; Hybrid tumor; Immunohistochemistry; Keratin-7 - analysis; Kidney cancer; Kidney Neoplasms - chemistry; Kidney Neoplasms - genetics; Kidney Neoplasms - pathology; Mitotic Index; Molecular Diagnostic Techniques; Morphology; Oncocytoma; Pathologists; Pathology; Predictive Value of Tests; Prognosis; Surveillance; Tumor classification; Tumors; Urologists; Urology; Immunohistochemistry; Oncocytoma; Chromophobe renal cell carcinoma; Diagnostic criteria; Tumor classification; Hybrid tumor
• ISSN: 0046-8177; 1532-8392
• DOI: 10.1016/j.humpath.2017.03.004

Summary Renal oncocytoma and chromophobe renal cell carcinoma (RCC) have been long recognized as distinct tumors; however, it remains unknown if uniform diagnostic criteria are used to distinguish these tumor types in practice. A survey was distributed to urologic pathologists regarding oncocytic tumors. Responses were received from 17/26 invitees. Histologically, >1 mitotic figure was regarded as most worrisome (n = 10) or incompatible (n = 6) with oncocytoma diagnosis. Interpretation of focal nuclear wrinkling, focal perinuclear clearing, and multinucleation depended on extent and did not necessarily exclude oncocytoma if minor. Staining techniques most commonly used included: CK7 (94%), KIT (71%), vimentin (65%), colloidal iron (59%), CD10 (53%), and AMACR (41%). Rare CK7-positive cells (≤5%) was regarded as most supportive of oncocytoma, although an extent excluding oncocytoma was not universal. Multiple chromosomal losses were most strongly supportive for chromophobe RCC diagnosis (65%). Less certainty was reported for chromosomal gain or a single loss. For tumors with mixed or inconclusive features, many participants use an intermediate diagnostic category (82%) that does not label the tumor as unequivocally benign or malignant, typically “oncocytic neoplasm” or “tumor” with comment. The term “hybrid tumor” was used variably in several scenarios. A slight majority (65%) report outright diagnosis of oncocytoma in needle biopsies. The morphologic, immunohistochemical, and genetic characteristics that define oncocytic renal tumors remain incompletely understood. Further studies correlating genetics, behavior, and histology are needed to define which tumors truly warrant classification as carcinomas for patient counseling and follow-up strategies.