A case of breast cancer with cartilage-like structure is presented. The stroma, resembling cartilagenous martrix upon hematoxylin and eosin staining, showed metachromasia upon toluidine blue staining. However, predigestion with hyaluronidase or chondroitinase ABC revealed no change in toluidine blue (pH 2.5) staining, suggesting the absence of not only hyaluronic acid but also of chondroitin sulfate in this structure. It is therefore reasonable to conclude that the cartilage-like structure found in this case may have been derived from epithelial mucinous substances, similar to those observed in common mucinous carcinoma of the breast.
Breast Neoplasms Carcinoma