title: Stromal cells of the fibroadenoma of the human breast. An immunohistochemical and ultrastructural study.
abstract: Fourteen fibroadenomas of the human breast were examined by light and electron microscopy, and by immunohistochemistry for actin. They were classified into 3 groups according to their stromal patterns; myxoid, fibrous-cellular and sclerotic. Actin immunohistochemistry revealed that the stromal areas were strongly positive in the fibrous-cellular group and weakly positive in the myxoid and sclerotic groups. By electron microscopy the stromal cells in most cases of the myxoid and fibrous-cellular groups were fibroblasts, containing varying amounts of microfilaments, 5-7 nm in diameter (actin type filaments). However, a dense body was not usually present suggesting these stromal cells were variants of myofibroblasts. The amount of microfilaments in fibroblasts was greater in the fibrous-cellular group than in the myxoid group. This was consistent with the results of actin immunohistochemistry. In 3 cases of the fibrous-cellular group peculiar structures simulating Z-lines of striated muscles were noted in some stromal cells. Since no myosin filaments were detected, they were regarded as intermediate structures between Z-lines of striated muscles and dense bodies of smooth muscles. In the sclerotic group, stromal fibroblasts were sparse and had fewer organelles.
mesh_terms: D000199:Actins / Q000378:metabolism; D000232:Adenofibroma / Q000473:pathology*; D000328:Adult; D001943:Breast Neoplasms / Q000473:pathology*; D003599:Cytoskeleton / Q000648:ultrastructure; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D008854:Microscopy, Electron
chemical_list: D000199:Actins