Infiltrating mammary carcinoma with osteoclast-like giant cells.

Mammary carcinoma with osteoclast-like giant cells is an uncommon variant. The following case examines a 36-year-old woman incidentally found to have a left breast mass on routine physical exam. Initial ultrasound-guided core biopsies revealed infiltrating mammary carcinoma with focal mucinous features, for which a left breast lumpectomy and sentinel lymph node biopsy were performed. The sentinel lymph nodes were positive for metastatic mammary carcinoma with osteoclast-like giant cells on permanent section corresponding to the lumpectomy breast specimen, thus a left completion axillary node dissection was subsequently performed.