title: Metanephric adenoma: the utility of immunohistochemical and cytogenetic analyses in differential diagnosis, including solid variant papillary renal cell carcinoma and epithelial-predominant nephroblastoma.
abstract: Metanephric adenoma is a benign renal neoplasm that overlaps in morphology with the solid variant of papillary renal cell carcinoma and epithelial-predominant nephroblastoma. To aid in resolving this differential diagnosis, we investigated the utility of immunohistochemical and molecular analyses in distinguishing between these entities; the first study, to our knowledge, to use a combined approach in analyzing all three tumors. We analyzed 37 tumors originally diagnosed as metanephric adenomas (2 of which we reclassified as papillary renal cell carcinomas), 13 solid variant papillary renal cell carcinomas, and 20 epithelial-predominant nephroblastomas using a combination of immunohistochemistry and fluorescence in situ hybridization (FISH) assessing for trisomy of chromosomes 7 and 17 and loss of Y. Immunohistochemical staining was performed for CK7, AMACR, WT1, and CD57. The combination of CK7-, AMACR-, WT1+, and CD57+ was considered characteristic of metanephric adenoma. Most of the tumors originally diagnosed as metanephric adenomas (31/37) showed the expected staining pattern of metanephric adenoma (CK7-, AMACR-, WT1+, and CD57+). Of the six tumors with discordant immunophenotype, two tumors were reclassified as papillary renal cell carcinoma after cytogenetic workup. It is recommended that all adult cases histologically resembling metanephric adenoma have WT1, CD57, CK7, and AMACR immunohistochemical staining performed. If the staining pattern is characteristic for metanephric adenoma (CK7-, AMACR-, WT1+, and CD57+, including membranous staining), then no other diagnostic tests are indicated. However, if there is a different immunostaining pattern, then we recommend FISH analysis.
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Stephanie N
authors.initials: SN
authors.lastname: Kinney
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: John N
authors.initials: JN
authors.lastname: Eble
authors.affiliation: Department of Pathology, Charles University Hospital Plzeň, Pilsen, Czech Republic.
authors.forename: Ondrej
authors.initials: O
authors.lastname: Hes
authors.affiliation: Department of Pathology and Laboratory Medicine, Henry Ford Health System, Detroit, MI, USA.
authors.forename: Sean R
authors.initials: SR
authors.lastname: Williamson
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Grignon
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Shaobo
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Lee Ann
authors.initials: LA
authors.lastname: Baldrige
authors.affiliation: Dipartimento di Patologia, Universitá di Verona, Verona, Italy.
authors.forename: Guido
authors.initials: G
authors.lastname: Martignoni
authors.affiliation: Dipartimento di Patologia, Universitá di Verona, Verona, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Brunelli
authors.affiliation: Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, China.
authors.forename: Lisha
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Pathology, Groupe Hospitalier Pitié-Salpêtrière, Paris, France.
authors.forename: Eva
authors.initials: E
authors.lastname: Comperat
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Fan
authors.affiliation: Department of Pathological Anatomy and Histopathology, School of Medicine, Polytechnic University of the Marche Region (Ancona), Ancona, Italy.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Montironi
authors.affiliation: Department of Pathology and Laboratory Medicine, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: Gregory T
authors.initials: GT
authors.lastname: MacLennan
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Cheng
mesh_terms: D000236:Adenoma / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D002292:Carcinoma, Renal Cell / Q000175:diagnosis; D002648:Child; D020732:Cytogenetic Analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007680:Kidney Neoplasms / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009396:Wilms Tumor / Q000175:diagnosis; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor