[Malignant phyllodes tumor of the breast with osteoclast-like giant cells: a case report].

Breast tumors, particularly of stromal origin, containing multinucleated osteoclast-like giant cells (OLGC) are rarely reported in the literature. We report here the first case of a malignant phyllodes tumor associated with OLGC occurring in a 43 year-old African woman who presented with a painful palpable mass of the outer upper quadrant of the right breast. After surgical excision, histological examination showed a malignant phyllodes tumor in which the stromal component displayed evident sarcomatous changes and was densely populated with benign multinucleated OLGC. These cells expressed the CD68 histiocytic marker. No evidence of osseous or cartilaginous differentiation was seen throughout the lesion. This lesion ressembles giant cell tumor of bone. However, the nature of the OLGC is not well precised yet.