Microscopic examination of the PC of the breast. (A) Low power view showed a diffuse proliferation of large and highly atypical cells devoid of adhesive characteristics, including many multi-nucleated bizarre giant cells (inset), arranged predominantly in a haphazard fashion with a chronic and acute inflammatory infiltrate (H&E stains). Bar = 400 μm. (B) While, a small amount of sarcomatoid components, consisted mainly of atypical spindle cells (inset), coexisted. Our careful histological examination revealed neither evidences of squamous nor chondro-osseous metaplasia (H&E stains). Bar = 1,000 μm. (C) On high-power view, emperipolesis of inflammatory cells was sometimes recognized (H&E stains). Bar = 100 μm. (D) The cystic cavity was surrounded by hemorrhagic and inflammatory granulation tissue and lined by mostly denuded but single atypical giant bizarre tumor cells or bland-looking flattened epithelial cells (inset) (H&E stains). Bar = 200 μm.