title: Mast Cells Are Abundant in Primary Cutaneous T-Cell Lymphomas: Results from a Computer-Aided Quantitative Immunohistological Study.
abstract: BACKGROUND
  Mast cells (MC) are bone marrow derived haematopoetic cells playing a crucial role not only in immune response but also in the tumor microenvironment with protumorigenic and antitumorigenic functions. The role of MC in primary cutaneous T-cell lymphomas (CTCL), a heterogeneous group of non-Hodgkin lymphomas with initial presentation in the skin, is largely unknown.
  
  
  OBJECTIVE
  To gain more accurate information about presence, number, distribution and state of activation (degranulated vs. non-degranulated) of MC in CTCL variants and clinical stages.
  
  
  METHODS
  We established a novel computer-aided tissue analysis method on digitized skin sections. Immunohistochemistry with an anti-MC tryptase antibody was performed on 34 biopsies of different CTCL subtypes and on control skin samples. An algorithm for the automatic detection of the epidermis and of cell density based CTCL areas was developed. Cells were stratified as being within the CTCL infiltrate, in P1 (a surrounding area 0-30 μm away from CTCL), or in P2 (30-60 μm away from CTCL) area.
  
  
  RESULTS
  We found high MC counts within CTCL infiltrates and P1 and a decreased MC number in the surrounding dermis P2. Higher MC numbers were found in MF compared to all other CTCL subgroups. Regarding different stages of MF, we found significantly higher mast cell counts in stages IA and IB than in stages IIA and IIB. Regarding MC densities, we found a higher density of MC in MF compared to all other CTCL subgroups. More MC were non-degranulated than degranulated.
  
  
  CONCLUSIONS
  Here for the first time an automated method for MC analysis on tissue sections and its use in CTCL is described. Eliminating error from investigator bias, the method allows for precise cell identification and counting. Our results provide new insights on MC distribution in CTCL reappraising their role in the pathophysiology of CTCL.
authors.affiliation: Department of Dermatology and Venereology, Karl Landsteiner University of Health Sciences, St. Pölten, Austria.|Karl Landsteiner Institute of Dermatological Research, St. Pölten, Austria.
authors.forename: Johanna
authors.initials: J
authors.lastname: Eder
authors.affiliation: Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria.|TissueGnostics GmbH, Vienna, Austria.
authors.forename: Radu
authors.initials: R
authors.lastname: Rogojanu
authors.affiliation: Department of Dermatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Waltraud
authors.initials: W
authors.lastname: Jerney
authors.affiliation: Laboratory for Tumor Immunology, CCRI St. Anna Kinderkrebsforschung, Vienna, Austria.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Erhart
authors.affiliation: Laboratory for Tumor Immunology, CCRI St. Anna Kinderkrebsforschung, Vienna, Austria.
authors.forename: Alexander
authors.initials: A
authors.lastname: Dohnal
authors.affiliation: Institute of Clinical Pathology, Karl Landsteiner University of Health Sciences, St. Pölten, Austria.
authors.forename: Melitta
authors.initials: M
authors.lastname: Kitzwögerer
authors.affiliation: TissueGnostics GmbH, Vienna, Austria.
authors.forename: Georg
authors.initials: G
authors.lastname: Steiner
authors.affiliation: Department of Dermatology and Venereology, Karl Landsteiner University of Health Sciences, St. Pölten, Austria.|Karl Landsteiner Institute of Dermatological Research, St. Pölten, Austria.
authors.forename: Julia
authors.initials: J
authors.lastname: Moser
authors.affiliation: Department of Dermatology and Venereology, Karl Landsteiner University of Health Sciences, St. Pölten, Austria.|Karl Landsteiner Institute of Dermatological Research, St. Pölten, Austria.
authors.forename: Franz
authors.initials: F
authors.lastname: Trautinger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015550:Cell Degranulation; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007150:Immunohistochemistry / Q000379:methods; D016410:Lymphoma, T-Cell, Cutaneous / Q000473:pathology*; D008297:Male; D008407:Mast Cells / Q000473:pathology* / Q000502:physiology; D008875:Middle Aged; D009182:Mycosis Fungoides / Q000473:pathology; D012878:Skin Neoplasms / Q000473:pathology; D055815:Young Adult