HISTOPATHOLOGICAL AND IMMUNOHISTOCHEMICAL STUDIES OF ACQUIRED TRACHEOBRONCHOMALACIA - AN AUTOPSY CASE-REPORT

A 72-year-old patient was reported to have 'saber-sheath-type' acquire d tracheobronchomalacia after irradiation therapy for laryngeal cancer . The pathogenetic features of this case were demonstrated immunohisto pathologically using CD68, HLA-DR, UCHL1, L26 and Ki-67 antibodies. Th e principal features were (a) selective destruction of the cartilage w ith Ki-67 stainability from the trachea to the segmental bronchi with inflammatory infiltrations of predominant T lymphocytes (UCHL1-positiv e) and activated macrophages (CD68-positive with marked HLA class II a ntigen) and (b) replacement by collagen fibers through the affected le sion. The tissues, except for the cartilage in the airway tract, were preserved without marked change, including the membranous portion. The cartilage at organs other than the airway showed no changes. We first clarified the immunohistopathology of tracheobronchomalacia. We propo sed that the characteristic cell-mediated immunity against cartilage w ith T lymphocytes and activated macrophages in the pathogenetic featur es may be related to a cancer-healing tendency.