title: Elastofibroma: a histochemical, immunohistochemical, and ultrastructural study of two patients.
abstract: Elastofibroma is a rare neoplasm. In this article, we report our study of the pathogenesis of fibrosis in elastofibroma. Three tumors obtained from two patients were selected. One patient was a 57-year-old Japanese woman who had a bilateral tumor, and the other patient was a 83-year-old Japanese man. All tumors occurred in the infrascapular region. Macroscopically, the cut surface of all tumors showed a poorly defined and whitish mass with yellowish foci. Microscopically, the tumor consisted of collagen fiber bundles, abnormal elastic fibers, and spindle cells suggestive of fibroblasts. Elastica-van Gieson and Masson-trichrome stain identified abnormal elastic fibers and abundant collagen fibers, respectively, in elastofibroma. Immunohistochemically, fibroblasts were positive for CD34 but negative for alpha-smooth muscle actin and h-caldesmon. Additionally, the cytoplasm of many fibroblasts was positive for TGF-beta in all tumors. Ultrastructurally, some fibroblasts with abundant organelles in one tumor were observed in the adjacent area to amorphous elastic mass and bundles of collagen fibers. However, no myofibroblasts were ultrastructurally identified in the tumor. Finally, our study supplies further evidence that elastofibroma may show the proliferation of CD34-positive fibroblasts and contain no myofibroblasts, and that fibroblasts may produce both abnormal elastic fibers and collagen fibers through the secretion of TGF-beta.
authors.affiliation: Department of Diagnostic Pathology, Kochi Red Cross Hospital, 2-13-51 Shin-honmachi, Kochi 780-8562, Japan. kurochankochi@yahoo.co.jp
authors.forename: Naoto
authors.initials: N
authors.lastname: Kuroda
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Hamaguchi
authors.forename: Masahiko
authors.initials: M
authors.lastname: Ohara
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirouchi
authors.forename: Keiko
authors.initials: K
authors.lastname: Mizuno
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Gang-Hong
authors.initials: GH
authors.lastname: Lee
mesh_terms: D000369:Aged, 80 and over; D018952:Antigens, CD34 / Q000378:metabolism; D004547:Elastic Tissue / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure*; D005260:Female; D005350:Fibroma / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D012983:Soft Tissue Neoplasms / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure*; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D018952:Antigens, CD34; D016212:Transforming Growth Factor beta