Fine needle aspiration cytology, immunocytochemistry and electron microscopy in a rare case of carcinoma of the breast with malignant epithelial giant cells.

The cytohistologic findings in a fine needle aspirate from a case of the rare breast carcinoma with bizarre tumor giant cells are described, along with the results of immunocytochemical and ultrastructural studies. The observations in this case suggest that the bizarre malignant giant cells in this type of breast cancer are of an epithelial origin, rather than a histiocytic-stromal origin. The other conditions that may yield giant cells in needle aspirates of breast masses are briefly discussed.