Immunohistological and electron microscopical study of nodular fasciitis of the orbit.

We report the case of a 7-year-old Japanese girl with nodular fasciitis which was investigated by immunohistological and electron microscopical methods. An excised nodular lesion in her right orbit showed characteristic histological features of the disease. The fibroblastic cells showed myofibroblastic characteristics, such as immunohistochemically positive reactions against muscle specific actin and vimentin and characteristic electron microscopical appearances. The multinuclear giant cells did not react against any histiocytic markers, including HLA-DR, antimacrophage antigen, lysozyme, and S-100 protein, but the myofibroblastic markers and the electron microscopical study did reveal myofibroblastic characters.