Infiltrating ductal carcinoma of the breast with rhabdoid phenotype.

Two cases of ductal cancers of the breast of no special type with a prominent rhabdoid component are presented. The mastectomy specimens showed the tumors to be composed of cells with a characteristic rhabdoid phenotype: Large cells with eccentric nuclei containing large inclusion like nucleoli and abundant eosinophilic cytoplasm. Immunohistochemistry showed typical immunoreactivity with cytoplasmic dot-like accentuation for epithelial markers as well as vimentin. In case 1, although excision margins were clear, tumor recurrence, composed mainly of rhabdoid cells, occurred within 7 months, and the patient died 2 months later. The second case, unfortunately, was lost to follow-up. This report is the second documenting the occurrence of rhabdoid cells in breast cancer. In keeping with other epithelial malignancies that contain rhabdoid cells, aggressive biological behavior is noted. Int J Surg Pathol 9(3):237-239, 2001