title: Multifocal, nascent, and invasive myoepithelial carcinoma (malignant myoepithelioma) of the breast: an immunohistochemical and ultrastructural study.
abstract: This report describes the light microscopic (LM), immunohistochemical (IHC), and electron microscopic (EM) features of a multifocal, nascent, and invasive myoepithelial carcinoma of the breast. By LM, the spindle cells disclosed fibrillar acidophilic cytoplasm, mild nuclear atypia, and a low mitotic index. Myoepithelial differentiation was established through IHC (single- and double-labeling techniques) and EM: periductal and infiltrating spindle cells coexpressed total muscle actin, alpha-smooth muscle actin, vimentin, cytokeratin 14, and pankeratin, and their EM features were characteristic of myoepithelial cells, i.e., perinuclear tonofilaments, subplasmalemmal bundles of microfilaments with dense bodies, intermediate junctions, poorly developed desmosomes, pinocytic vesicles, and fragmented external lamina. No invasive epithelial cells disclosed luminal differentiation (by LM, IHC, EM), identifying, thus, this neoplasm as a pure spindle cell myoepithelial carcinoma of the breast.
authors.affiliation: Université de Montréal, Montréal, Québec, Canada.
authors.forename: Francine
authors.initials: F
authors.lastname: Jolicoeur
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Seemayer
authors.forename: Giulio
authors.initials: G
authors.lastname: Gabbiani
authors.forename: André
authors.initials: A
authors.lastname: Robidoux
authors.forename: Louis
authors.initials: L
authors.lastname: Gaboury
authors.forename: Luc L
authors.initials: LL
authors.lastname: Oligny
authors.forename: Walter
authors.initials: W
authors.lastname: Schürch
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry / Q000473:pathology / Q000601:surgery; D002467:Cell Nucleus / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D009208:Myoepithelioma / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000032:analysis; D009378:Neoplasms, Multiple Primary
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins