title: CD138 expression in renal tumors and its usage in the differential diagnosis.
abstract: OBJECTIVE
  The differential diagnosis of kidney tumors, especially those with eosinophilic cytoplasms, can be problematic due to overlapping morphologic features. CD138 is primarily a plasma cell marker but is known to be expressed in the proximal renal tubular epithelium as well. This study aims to investigate the possible contribution of CD138 expression in the differential diagnosis of kidney tumors with eosinophilic cytoplasm.
  
  
  METHODS
  The case series consisted of 15 chromophobe (ChRCC), 5 eosinophilic variant (EoRCC), 10 clear cell (CCRCC) and 9 papillary (PRCC) renal cell carcinomas, and 13 oncocytomas. Sections obtained from representative paraffin blocks were stained against CD138 antibody.
  
  
  RESULTS
  All CCRCC and PRCC showed membranous CD138 expression. In some of the other eosinophilic renal tumors, cytoplasmic CD138 labeling in varying degrees was detected. In CCRCC cases, CD138 expression was especially observed in low grade areas and areas showing cystic and pseudopapillary growth patterns. A similar pattern of cytoplasmic staining was seen in 3 of the EoRCC and the most of the PRCC cases (6/9).
  
  
  CONCLUSIONS
  Our findings suggest that CD138 may contribute to the differential diagnosis of renal tumors because of the membranous staining pattern in CCRCC and EoRCC cases and the cytoplasmic staining in CHRCC and oncocytoma cases. Its contributory role may be improved by combined usage with markers like Cytokeratin 7 and RCC marker.
authors.affiliation: Department of Pathology, Gülhane Military Medical Academy, School of Medicine, Ankara, Turkey.
authors.forename: Ayhan
authors.initials: A
authors.lastname: Ozcan
authors.forename: Ertuğrul
authors.initials: E
authors.lastname: Celık
authors.forename: Yıldırım
authors.initials: Y
authors.lastname: Karslioğlu
authors.forename: Seref
authors.initials: S
authors.lastname: Basal
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000378:metabolism; D003937:Diagnosis, Differential; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D053668:Syndecan-1 / Q000032:analysis / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; C508241:SDC1 protein, human; D053668:Syndecan-1