Abstract
Background : Matrix-producing carcinoma (MPC) of the breast is a rare subtype of breast cancer, accounting for 0.03 to 0.2% of all breast cancers.
We report a case of MPC and its cytopathological features.
Case : A 53-year-old female presented with a hard mass in her left breast. Papanicolaou staining of fine-needle-aspiration cytology specimens showed atypical single cells and cell clusters in a pale green-stained myxoid background. There were three types of cell clusters : carcinomatous, chondromatous, and intermediate clusters in a chondroid matrix.
Histologically, the tumor had a chondromatous element at the center and a carcinomatous element in the peripheral region. The tumor demonstrated overt carcinoma with direct transition to a cartilaginous stromal matrix without an intervening spindle cell zone or osteoclastic cells ; based on these findings, we diagnosed the tumor as MPC.
Conclusion : It is possible to suspect MPC when both carcinomatous and chondromatous cell clusters appear on the same glass slide with transitional images of these cells. Thus, MPC may be suspected clinically based on its characteristic properties.
