Mammary carcinoma with osteoclast-like giant cells. A study of eight cases with follow-up data.

Eight cases of a rare, distinctive variant of infiltrating mammary carcinoma featuring benign multinucleated osteoclast-like giant cells are reported. The multinucleated osteoclast-like giant cells are reported. The multinucleated giant cells were associated with ductal carcinoma in five cases and with infiltrating lobular carcinoma in three cases. Although three patients had lymph nodal metastases in level one, none of the nodal metastases contained giant cells. From the limited follow-up data of this report, it seems likely that the prognosis for patients who have this type of adenocarcinoma is not especially favorable. The observation that the giant cells generally occurred in areas of prominent angiogenesis suggests that the angiogenesis may be induced by some chemical substance produced by the tumor cells. Biochemical and immunologic investigations may eventually provide an explanation for this unusual morphologic manifestation of host reaction to mammary carcinoma.