Ductal carcinoma in situ of the breast with osteoclast-like giant cells.

Mammary carcinoma with multinucleated osteoclast-like giant cells (OGCs) is a rare, distinctive variant of breast carcinoma. To date, all of these instances have been described as part of an invasive carcinoma. Here, we report a case of ductal carcinoma in situ of the breast with numerous admixed OGCs present within gland lumens without an associated invasive component. Similar to invasive carcinomas with OGCs, both the in situ carcinoma and the OGCs exhibited overexpression for vascular endothelial growth factor. This case expands the spectrum of tumors associated with OGCs and provides further evidence for the possible role of vascular endothelial growth factor in the stromal-epithelial interactions of in situ mammary carcinoma.