Background: Mammary carcinoma with osteoclastlike giant cells (OCLGCs) is a rare tumor. Few reports on the fine needle aspiration (FNA) findings are available. This case had cytologic findings overlapping with benign breast disease.
Case: A 50-year-old woman presented with multiple masses in her right breast and a 2-cm right axillary lymph node. Cytologic scrapings and FNA of the same breast mass showed large cohesive, two-dimensional epithelial cells with a uniform distribution of small, bland nuclei. Discohesion, single cells with features of malignancy, cytologic atypia and mitosis were lacking. Many OCLGCs were present.
Conclusion: The cytologic features of this rare type of breast carcinoma need to become familiar to pathologists to avoid a false negative diagnosis.