The presence of enlarged and pleomorphic nuclei is usually regarded as a feature of malignancy, but it may on occasion be seen in benign lesions such as mammary fibroadenomas. We present such a case of fibroadenoma occurring in a 37-year-old woman presenting with a self-palpable right breast mass. Histological examination of the tumor revealed the presence of multi and mononucleated giant cells with pleomorphic nuclei. The recognition of the benign nature of these cells is necessary for differential diagnosis from malignant lesions of the breast.
Keywords: fibroadenoma - pleomorphic stromal cells - atypia - breast.