title: Melanocytic matricoma: case confirmation of a recently described entity.
abstract: BACKGROUND
  In 1999, Carlson et al. reported two cases of a matrical neoplasm that recapitulates the bulb of the anagen hair follicle, which they designated as melanocytic matricoma.
  
  
  METHODS
  Here we report a similar case in a 78-year-old white male, who presented with a 0.4 cm purple-black firm papule in the left preauricular area.
  
  
  RESULTS
  Histologically, the tumor is composed of a dual cell population including admixed epithelial matrical and supramatrical cells with "shadow" cell formation and pigmented dendritic melanocytes. Immunohistochemical studies for cytokeratin highlighted the epithelial component and studies for S-100 protein, HMB-45, and vimentin confirmed the melanocytic component. The differential diagnosis considered includes pigmented variants of pilomatricoma, matrical carcinoma, basal cell carcinoma and malignant melanoma.
  
  
  CONCLUSIONS
  The case reported herein is the first confirmation of melanocytic matricoma, a distinctive adnexal neoplasm with characteristic clinical and pathologic features, which differentiate it from pigmented pilomatricoma.
authors.affiliation: Department of Pathology, University of South Alabama, Mobile, Alabama, USA.
authors.forename: Christy M
authors.initials: CM
authors.lastname: Williams
authors.forename: Peter
authors.initials: P
authors.lastname: Bozner
authors.forename: Cecilia V
authors.initials: CV
authors.lastname: Oliveri
authors.forename: Marcelo G
authors.initials: MG
authors.lastname: Horenstein
mesh_terms: D000368:Aged; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor / Q000378:metabolism; D006201:Hair Diseases / Q000378:metabolism / Q000473:pathology*; D018859:Hair Follicle / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D008544:Melanocytes / Q000378:metabolism / Q000473:pathology*; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins / Q000378:metabolism; D018294:Neoplasms, Adnexal and Skin Appendage / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D018296:Pilomatrixoma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D009418:S100 Proteins / Q000378:metabolism; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D014746:Vimentin / Q000378:metabolism
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D009418:S100 Proteins; D014746:Vimentin