title: Characterization of factor XIIIa+ dendritic cells in dermatofibroma: Immunohistochemical, electron and immunoelectron microscopical observations.
abstract: BACKGROUND
  Previous studies indicate that FXIIIa+ proliferative cells are the cells constituting DFs, however, in spite of the high incidence of DFs, there is a little information in the literature regarding ultrastructural characteristics of the FXIIIa+ dendritic cells on DFs.
  
  
  OBJECTIVE
  In this study, we examined the fine structures and potential heterogeneity among the subgroup of factor XIIIa (FXIIIa) positive dendritic cells consisted of eleven cases of dermatofibroma (DF).
  
  
  METHODS
  Immunohistochemical, electron microscopical, and immunoelectron microscopical techniques were utilized.
  
  
  RESULTS
  We demonstrated (i) the immunohistochemical labeling of FXIIIa and CD68 in the DFs. The reactivity was stronger in histiocytic lesions than in fibroblastic lesions. On the other hand, the labeling of HHF35 was mainly in fibroblastic lesions. (ii) The fibroblastic and histiocytic cells on DFs displayed the same basic fine structures; moderate or abundant rough endoplasmic reticulum (RER), lipid droplets and/or bundles of myofilaments in varying proportions. Macular adherence connections between neighboring cells were common. (iii) They also showed the similar features to dermal dendritic cells (DDC), which have been well characterized with long cytoplasmic processes, abundant RER, fibronexus-like plaques and pinocytotic vesicles. (iv) FXIIIa expressions were found within the cytoplasm of both fibroblastic and histiocytic cells in association with the nucleus by immunoelectron microscopy. The labeling was stronger in the histiocytic cells and the cells expressing elongated cytoplasmic processes than in the fibroblastic cells.
  
  
  CONCLUSIONS
  The FXIIIa+ dendritic cells might be an essential cell of DF, and might have potential to develop HHF35+ fibroblastic or CD68+ histiocytic cells, under appropriate stimuli. The FXIIIa+ dendritic cells might be originated from DDC.
authors.affiliation: Division of Dermatology, Graduate School of Medical and Dental Sciences, Niigata University, Japan. waso6268@med.niigata-u.ac.jp
authors.forename: Ying
authors.initials: Y
authors.lastname: Song
authors.forename: Fumiko
authors.initials: F
authors.lastname: Sakamoto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ito
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000096:biosynthesis / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D026122:Factor XIIIa / Q000096:biosynthesis*; D005347:Fibroblasts / Q000378:metabolism; D018219:Histiocytoma, Benign Fibrous / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008247:Lysosomes / Q000378:metabolism; D008854:Microscopy, Electron; D046529:Microscopy, Electron, Transmission; D016253:Microscopy, Immunoelectron; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology*; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D026122:Factor XIIIa; C067980:CD68 antigen, human; D000097382:CD68 Molecule