title: Cutaneous clear-cell granular cell tumors: the histologic description of an unusual variant.
abstract: BACKGROUND
  Granular cell tumors (GCTs) are neoplasms showing nerve sheath differentiation that can arise in the skin but, to our knowledge, have not been associated with significant clear-cell morphology.
  
  
  METHODS
  Two patients developed four separate GCTs with distinctive, diffuse clear-cell change, which completely camouflaged the primary differentiation. The morphology, histochemistry and immunohistochemistry of the lesions are described and are compared with the presence and extent of clear-cell change in 14 other cases of GCTs.
  
  
  RESULTS
  The index cases were relatively broad proliferations with uniform diffuse clear-cell change and only minimal overlying epidermal hyperplasia. Prominent lymphoid nodules were present at the periphery. These clear-cell granular tumors were positive for S-100 protein, p75, CD68, NKI/C3 and neuron-specific enolase and were negative for epithelial mucin, periodic acid-Schiff, carcinoembryonic antigen, HMB-45, Melan-A, smooth muscle actin, Leu7, synaptophysin, CD34, factor XIIIa, epithelial membrane antigen and cytokeratin. Three of the fourteen comparison cases were found to have no clear-cell change, eight showed focal clear-cell change and three showed moderate clear-cell change.
  
  
  CONCLUSIONS
  The distinctive morphology and the immunohistochemical results are discussed in the context of the differential diagnosis of clear-cell cutaneous tumors.
authors: Department of Pathology, University of North Carolina Hospitals, Chapel Hill, NC, USA.
authors: Daniel C
authors: DC
authors: Zedek
authors: Bettina A
authors: BA
authors: Murphy
authors: Christopher R
authors: CR
authors: Shea
authors: Michael G
authors: MG
authors: Hitchcock
authors: Jason C
authors: JC
authors: Reutter
authors: Wain L
authors: WL
authors: White
mesh_terms: D049309:Acanthoma / Q000473:pathology; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D016586:Granular Cell Tumor / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D012878:Skin Neoplasms / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor