title: Acquired Localized Longitudinal Pachyonychia and Onychomatrical Tumors: A Comparative Study to Onychomatricomas (5 Cases) and Onychocytic Matricomas (4 Cases).
abstract: BACKGROUND
  Besides onychomatricoma (OM), which shows a clinical band pattern of nail plate thickening, 2 new onychomatrical tumors with this clinical feature have recently been described: onychocytic matricoma (OCM) and in situ onychocytic carcinoma.
  
  
  OBJECTIVE
  The purpose of this study was to present 4 cases of OCMs and compare their clinical and histopathologic characteristics with usual OMs.
  
  
  METHODS
  We studied 4 cases of OCMs with nail clipping in 3 cases and an extensive immunohistochemical study for hair-related keratins and epithelial keratins. Nail clipping of OCMs was compared with the distal nail plate of 5 cases of OMs.
  
  
  RESULTS
  All cases showed an acquired localized longitudinal band pattern of a thickened nail plate with yellow discoloration in 2 cases and a black streak in 2 cases. All cases showed a V-shaped keratogenous epithelial tumor with a papillomatous pattern of growth. The nail plate was thickened with small holes in a honeycomb pattern. In contrast, the 5 OMs showed the classical pattern of a panonychoma fibropapilliferum. The nail plate showed large cavities in a honeycomb pattern.
  
  
  CONCLUSIONS
  This case series raises awareness of the clinical value of longitudinal pachyonychia coupled with nail clipping in the early detection of onychomatrical tumors as generic diagnosis with a limited differential diagnosis and a simple therapeutic approach. Nail clipping could be an aid in the surgical planning of onychomatrical tumor. A diagnosis of a benign growth could be suggested when the average dimensions of cavities are superior to 0.15 mm sparing the patient from an excisional procedure with its risk of subsequent permanent nail dystrophy. In contrast, nail clipping with a honeycomb pattern of minute cavities with average dimension inferior to 0.10 mm should prompt a biopsy of the distal matrix to rule out a malignant lesion.
authors.affiliation: *The Laboratoire Central d'Anatomie Pathologique, Hôpital L. Pasteur, University of Nice, Nice, France; †Nail's Dermatology Consultations, Cannes, France; ‡UOC Dermatologia, Ospedale Civile, Imperia, Italia; §Division of Genetic of Skin Carcinogenesis, Section of Normal and Neoplastic Epidermal Differentiation, German Cancer Research Center, Heidelberg, Germany; ¶Department of Pathology, West Kent Oncology Center, Maidstone Hospital, Hermitage Lane, England; ‖Service de Chirurgie Plastique, University of Nice, Nice, France; and **Institut Polyclinique de Cannes, Cannes, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Perrin
authors.forename: Giuseppe Emilio
authors.initials: GE
authors.lastname: Cannata
authors.forename: Lutz
authors.initials: L
authors.lastname: Langbein
authors.forename: Damien
authors.initials: D
authors.lastname: Ambrosetti
authors.forename: Michael
authors.initials: M
authors.lastname: Coutts
authors.forename: Thierry
authors.initials: T
authors.lastname: Balaguer
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Garzon
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Michiels
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009260:Nail Diseases / Q000473:pathology*; D009264:Nails, Malformed / Q000473:pathology*; D012878:Skin Neoplasms / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor