What happened, in summary

This 39-year-old woman presented with 2 lumps in her left breast. One hard, mobile mass in the upper inner quadrant measured about 4.0 × 4.5 cm, and a second upper-outer-quadrant mass had less defined borders and measured about 2.5 × 2.0 cm. CT and MRI confirmed 2 separate breast masses. Surgical excision showed that the smaller mass was invasive ductal carcinoma, while the larger mass was an inflammatory myofibroblastic tumor, a rare spindle-cell tumor that can mimic cancer clinically and radiographically. The breast cancer lesion showed ER positivity in 20% of cells, PR positivity in 40%, C-erbB-2/HER2 2+ staining in 80%, VEGF positivity, FGFR positivity, p53 positivity, and E-cadherin positivity. The inflammatory myofibroblastic tumor had a different profile, including ALK positivity, vimentin positivity, S-100 positivity, and desmin negativity. This distinction mattered because the larger mass was not ordinary breast carcinoma, but the smaller invasive ductal carcinoma still required definitive breast cancer treatment. Because breast cancer coexisted with the inflammatory tumor, she underwent a modified radical mastectomy of the left breast. Adjuvant treatment included 6 courses of TAC chemotherapy, consisting of Taxotere/docetaxel, Adriamycin/doxorubicin, and cyclophosphamide. She then took tamoxifen 10 mg twice daily. Her case is unusual because an inflammatory myofibroblastic tumor and invasive breast cancer were present at the same time in the same breast, making preoperative diagnosis difficult and requiring final pathologic examination to guide treatment. As of August 2013, she remained disease-free at 2-year follow-up, with no recurrent breast cancer or inflammatory myofibroblastic tumor described.