Utility of cytokeratin 7 for distinguishing chromophobe renal cell carcinoma from renal oncocytoma

Eur Urol. 2000 Apr;37(4):484-7. doi: 10.1159/000020172.


Objective: Chromophobe renal cell carcinoma is a relatively uncommon variant of renal carcinoma described in 1985. The main differential diagnosis is renal oncocytoma. Hale's colloidal iron staining is a powerful adjunct to morphological interpretation but it is not specific and is sometimes difficult to interpret. We studied the immunohistochemical expression of cytokeratin 7 to determine its value in distinguishing chromophobe renal cell carcinoma from renal oncocytoma.

Methods: Immunostaining was performed on paraffin-embedded tumor tissue of 6 chromophobe renal cell carcinomas and 11 oncocytomas with an antibody to cytokeratin 7 (clone OV-TL 12/30, Dako, France) using a streptavidin-biotin method.

Results: All chromophobe renal cell carcinomas showed strong cytoplasmic staining with peripheral cell accentuation. In contrast, 8 of 11 oncocytomas were entirely negative and 3 showed only weak and focal staining in less than 5% of the tumor cells.

Conclusion: Immunohistochemical staining for cytokeratin 7 may be useful for the differential diagnosis of renal oncocytomas and chromophobe renal cell carcinomas when Hale's colloidal iron staining is uncertain.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Adenocarcinoma / pathology*
  • Adenocarcinoma / surgery
  • Adenoma, Oxyphilic / pathology*
  • Adenoma, Oxyphilic / surgery
  • Adult
  • Aged
  • Aged, 80 and over
  • Biopsy, Needle
  • Carcinoma, Renal Cell / pathology*
  • Carcinoma, Renal Cell / surgery
  • Diagnosis, Differential
  • Female
  • Humans
  • Immunohistochemistry / methods
  • Keratin-7
  • Keratins*
  • Kidney Neoplasms / pathology*
  • Kidney Neoplasms / surgery
  • Male
  • Middle Aged
  • Sensitivity and Specificity


  • KRT7 protein, human
  • Keratin-7
  • Keratins