title: Diagnostic approach to eosinophilic renal neoplasms.
abstract: BACKGROUND
  Eosinophilic renal neoplasms include a spectrum of solid and papillary tumors ranging from indolent benign oncocytoma to highly aggressive malignancies. Recognition of the correct nature of the tumor, especially in biopsy specimens, is paramount for patient management.
  
  
  OBJECTIVE
  To review the diagnostic approach to eosinophilic renal neoplasms with light microscopy and ancillary techniques.
  
  
  METHODS
  Review of the published literature and personal experience.
  
  
  CONCLUSIONS
  The following tumors are in the differential diagnosis of oncocytic renal cell neoplasm: oncocytoma, chromophobe renal cell carcinoma (RCC), hybrid tumor, tubulocystic carcinoma, papillary RCC, clear cell RCC with predominant eosinophilic cell morphology, follicular thyroid-like RCC, hereditary leiomyomatosis-associated RCC, acquired cystic disease-associated RCC, rhabdoid RCC, microphthalmia transcription factor translocation RCC, epithelioid angiomyolipoma, and unclassified RCC. In low-grade nonpapillary eosinophilic neoplasms, distinction between oncocytoma and low-grade RCC mostly rests on histomorphology; however, cytokeratin 7 immunostain may be helpful. In high-grade nonpapillary lesions, there is more of a role for ancillary techniques, including immunohistochemistry for cytokeratin 7, CA9, CD10, racemase, HMB45, and Melan-A. In papillary eosinophilic neoplasms, it is important to distinguish sporadic type 2 papillary RCC from microphthalmia transcription factor translocation and hereditary leiomyomatosis-associated RCC. Histologic and cytologic features along with immunohistochemistry and fluorescence in situ hybridization tests for TFE3 (Xp11.2) and TFEB [t(6;11)] are reliable confirmatory tests. Eosinophilic epithelial neoplasms with architecture, cytology, and/or immunoprofile not qualifying for either of the established types of RCC should be classified as unclassified eosinophilic RCC and arbitrarily assigned a grade (low or high).
authors.affiliation: From the Departments of Pathology (Drs Kryvenko and Jorda) and Urology (Drs Kryvenko and Jorda), University of Miami Miller School of Medicine, Miami, Florida; and the Departments of Pathology (Drs Argani and Epstein), Oncology (Drs Argani and Epstein), and Urology (Dr Epstein), The Johns Hopkins Medical Institutions, Baltimore, Maryland.
authors.forename: Oleksandr N
authors.initials: ON
authors.lastname: Kryvenko
authors.forename: Merce
authors.initials: M
authors.lastname: Jorda
authors.forename: Pedram
authors.initials: P
authors.lastname: Argani
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Epstein
mesh_terms: D018249:Adenoma, Oxyphilic / Q000175:diagnosis / Q000473:pathology; D018207:Angiomyolipoma / Q000175:diagnosis / Q000473:pathology; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics; D002292:Carcinoma, Renal Cell / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D041321:Chromosomes, Human, X / Q000235:genetics; D004802:Eosinophilia / Q000473:pathology*; D005260:Female; D006801:Humans; D052177:Kidney Diseases, Cystic / Q000150:complications / Q000473:pathology; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000209:etiology / Q000235:genetics / Q000473:pathology*; D018231:Leiomyomatosis / Q000175:diagnosis / Q000473:pathology; D008297:Male; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics; D009386:Neoplastic Syndromes, Hereditary; D012878:Skin Neoplasms / Q000175:diagnosis / Q000473:pathology; D014178:Translocation, Genetic; D014594:Uterine Neoplasms / Q000175:diagnosis / Q000473:pathology
chemical_list: D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D051739:Microphthalmia-Associated Transcription Factor; C069203:TFE3 protein, human