title: Cutaneous granular cell tumor with epidermal involvement: a potential mimic of melanocytic neoplasia.
abstract: BACKGROUND
  Cutaneous granular cell tumor (GCT) may present with extension into the junctional region of the epidermis and thus may mimic melanocytic neoplasms.
  
  
  METHODS
  We reviewed three cases of cutaneous GCT where a melanocytic neoplasm was either initially diagnosed or considered in the differential diagnosis. Histopathology was evaluated in regards to features associated with melanocytic neoplasms. Immunohistochemistry was performed to delineate a panel useful in the distinction of these and other entities.
  
  
  RESULTS
  All cases consisted of spindle and epithelioid cells with granular cytoplasm and bland nuclei and were centered in the superficial dermis with extension into the epidermis. Two cases resembled Spitz nevi and one case demonstrated lentiginous growth. All cases stained positively with calretinin and inhibin. Two of the three cases stained diffusely with S100 and 2/2 cases with CD56. HAM56 and CD68 were positive in one case and another showed positivity for NSE and PGP9.5. HMB-45, tyrosinase, and Melan-A were non-reactive in all cases tested.
  
  
  CONCLUSIONS
  GCT may involve the epidermis and has a growth pattern similar to melanocytic neoplasms. An immunohistochemical (IHC) panel including S100, Melan-A, tyrosinase, HMB-45, CD56, CD68, calretinin, inhibin, and PGP9.5 may aid in the distinction and may spare the patient from unnecessary morbidity.
authors.affiliation: Department of Dermatology, University of Pittsburgh School of Medicine, Pittsburgh 15232, PA, USA. rays@upmc.edu
authors.forename: Sourav
authors.initials: S
authors.lastname: Ray
authors.forename: Drazen M
authors.initials: DM
authors.lastname: Jukic
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D064032:Calbindin 2; D003937:Diagnosis, Differential; D015622:Epithelioid Cells / Q000737:chemistry / Q000473:pathology; D005260:Female; D016586:Granular Cell Tumor / Q000737:chemistry / Q000473:pathology*; D006801:Humans; D007265:Inhibins / Q000032:analysis; D008545:Melanoma / Q000175:diagnosis*; D064030:S100 Calcium Binding Protein G / Q000032:analysis; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; C576764:CALB2 protein, human; D064032:Calbindin 2; D064030:S100 Calcium Binding Protein G; D007265:Inhibins