title: A rippled-pattern trichoblastoma: an immunohistochemical study.
abstract: BACKGROUND
  Since the first description by Hashimoto et al., there have been only a few case reports of rippled-pattern tricogenic tumor. In addition, there are no reports on detailed immunohistochemical analyses of this rare neoplasm. We describe here an additional case of rippled-pattern trichogenic tumor with a special reference to its immunohistochemical features.
  
  
  METHODS
  A nodule arising on the occipital area of a 62-year-old Japanese woman was histologically and immunohistochemically investigated.
  
  
  RESULTS
  Histopathologically, the lesion contained various-sized lobular nests, which consisted of oval to elliptical shaped basaloid cells without any atypia and were embedded in the collagenous stroma. Some elongated basaloid cells were arranged in a palisading fashion forming parallel rows of epithelial ribbons in a rippled-pattern. Cytokeratin (CK) immunohistochemistry showed constant expressions of CK1/5/ 10/14, CK5/8, CK14 and CK7, and focal expressions of CK17 and CK19 in the basaloid cells, suggesting a keratin phenotypical similarity to the cells in small nodular type trichoblastoma.
  
  
  CONCLUSIONS
  The present tumor is a variant of trichoblastoma, and considered to be in close association with the outer root sheath and/ or follicular germinative cells.
authors.affiliation: Department of Dermatology and Occupational Dermatopathology, School of Medicine, University of Occupational and Environmental Health Japan, Kitakyushu. yamasam@med.uoeh-u.ac.jp
authors.forename: O
authors.initials: O
authors.lastname: Yamamoto
authors.forename: M
authors.initials: M
authors.lastname: Hisaoka
authors.forename: H
authors.initials: H
authors.lastname: Yasuda
authors.forename: D
authors.initials: D
authors.lastname: Nishio
authors.forename: M
authors.initials: M
authors.lastname: Asahi
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D005260:Female; D006201:Hair Diseases / Q000378:metabolism / Q000473:pathology*; D018859:Hair Follicle / Q000737:chemistry / Q000473:pathology*; D006801:Humans; D007124:Immunoenzyme Techniques; D007633:Keratins / Q000032:analysis; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D018295:Neoplasms, Basal Cell / Q000737:chemistry / Q000473:pathology*; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D007633:Keratins