シェーグレン症候群の耳下腺における筋上皮島の三次元構築と微細構造

抄録

Benign lymphoepithelial lesions of the salivary glands associated with Sjögren's syndrome are characterized by extensive infiltration of lymphoid cells, atrophy of acini and the presence of epimyoepithelial islands. This report describes our three dimensional reconstructive study of epimyoepithelial islands using computer graphics. Ultrastructural and immunohistochemical studies were also performed with several antibodies: KL-1, actin, PanB and PanT. The monoclonal antibody KL-1 intensely stained duct cells of the normal parotid gland. Most of the cells composing epimyoepithelial islands were positive for KL-1, but they were negative for actin. PanB-positive cells were dominant among the lymphoid cells of the stroma and were scattered in the epimyoepithelial islands. The reconstructive study proved that epimyoepithelial islands are continuous duct-like structures rather than isolated cell clusters. Ultrastructural examination showed that epimyoepithelial islands are composed mainly of epithelial cells containing intermediate filaments. Myoepithelium-like cells containing myofilaments were rarely found in the peripheral portion of the islands. These results suggest that epimyoepithelial islands are derived from proliferating duct epithelial cells.