[Osteoclastic type giant cell carcinoma of the breast]

Five cases of mammary carcinoma with osteoclast-like giant cells are reported. This study as well as review of the literature underline characteristic features of this rare histological type of carcinoma: a round well-circumscribed dense nodule of benign appearance on mammograms in half of the cases; brown colour of tumour specimens; stromal hypervascularity; negativity of epithelial, vascular and most histiocytic immunohistochemical markers in giant cells; positivity of leucocyte common antigen and vimentin in giant cells. Giant cells most probably originate from the fusion of histiocytic type mononucleated stromal cells, but results of immunohistochemical stainings cannot actually bring formal arguments to support this hypothesis.