A case of spindle cell carcinoma of the breast arising within a mammary cyst is reported.
A 42-year-old female who had a familial history of breast cancer visited the outpatient clinic at our hospital complaining of a lump in the left breast. A tumor measuring 2 cm in diameter was palpated in the upper inner quadrant of her left breast. The ultrasonic finding showed a slightly low echo in the cystic region.
Light yellow brown fluids were aspirated from the tumor by fine needle and the tumor disappeared. These aspirates were diagnossed as class I cytologically.
Two months after the first visit, she visited our clinic again complaining of a 3.5 cm sized tumor in the same region.
Ultrasonography showed an increased low echoic part in the cyst. Several supplemental diagnostic examinations were performed, but the exact diagnosis could not be confirmed. Therefore surgical biopsy was done.
Pathohistologically the tumor was diagnosed as infiltrating ductal carcinoma containing spindle cells, while immunohistochemical evidence of both epithelial markers (Epithelial Membrane Antigen, Cytokeratin AE1/AE3) and mesenchymal marker (Vimentin) were positive.
Immunohistochemically, estrogen receptor was storongly positive, while progesterone receptor and human epidermal growth factor2 were negative and the Ki67 index was 87.2 ％.
Total mastectomy and axillary lymph node (Ｉ-group) dissection were performed. The remains of fine DCIS were found and one lymphnode metastasis which was stained positive by cytokeratin staining.
Adjuvant chemotherapy was administerd with 4 cycles of FEC (Fluorouracil, Epirubicin hydrochloride, Cyclophosphamide) and Docetaxel, and was followed by adjuvant endocrine therapy with Tamoxifen citrate. Three years and six months after surgery no evidence of recurrence was observed in the outpatient clicic.
The possibility of spindle cell carcinoma should be kept in mind in patients with a familial history of breast cancer who show cystic regions on ultrasound.