title: Clear-cell papillary renal cell carcinoma: 24 cases of a distinct low-grade renal tumour and a comparative genomic hybridization array study of seven cases.
abstract: OBJECTIVE
  To report clinicopathological and genomic characteristics of (ccpRCC), a rare, recently characterized renal tumour entity.
  
  
  RESULTS
  Twenty-four renal tumours identified as ccpRCC were collected. Data from comparative genomic hybridization on microarrays (array-CGH) were obtained for seven of these. Most tumours (58%) occurred in the absence of renal disease. Mean patient age was 58.1 years. Tumours were small (mean size: 2.4 cm) and classified as pT1. Histological characteristics consisted of tubules and papillae lined by a single layer of small clear cells harbouring low-grade nuclei (Fuhrman grades 1 or 2). Architectural variations, with compact areas (41% of cases) and a micro- or macrocystic pattern (67% of cases) were observed frequently. Immunostaining demonstrated diffuse, strong expression of cytokeratin 7 and vimentin, whereas CD10, racemase, RCC antigen, translocation factor E3, TFE3 and translocation factor EB were consistently negative. In seven tumours, array-CGH detected no chromosomal imbalances.
  
  
  CONCLUSIONS
  Clear-cell papillary renal cell carcinoma (ccpRCC) were differentiated from other renal neoplasms by a specific constellation of histopathological and immunohistochemical features, without characteristic genomic imbalances. Clinical, histopathological and genomic data suggested that these tumours have a low potential for malignancy.
authors.affiliation: Department of Pathology, Hôpital Necker-Enfants Malades, AP-HP, Paris Université Paris Descartes, Paris, France. julien.adam@nck.aphp.fr
authors.forename: Julien
authors.initials: J
authors.lastname: Adam
authors.forename: Jérôme
authors.initials: J
authors.lastname: Couturier
authors.forename: Vincent
authors.initials: V
authors.lastname: Molinié
authors.forename: Annick
authors.initials: A
authors.lastname: Vieillefond
authors.forename: Mathilde
authors.initials: M
authors.lastname: Sibony
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D002292:Carcinoma, Renal Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002869:Chromosome Aberrations; D055028:Comparative Genomic Hybridization / Q000379:methods*; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D006801:Humans; D053552:Keratin-7 / Q000378:metabolism; D007680:Kidney Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy; D020411:Oligonucleotide Array Sequence Analysis; D014746:Vimentin / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D053552:Keratin-7; D014746:Vimentin