A case of apocrine carcinoma of the breast presenting as two cysts

A case of apocrine carcinoma of the breast presenting as two cysts is reported. A 60-year-old woman had two soft, mobile, well-defined masses measuring 4 X 2.5 cm and 1.5 X 2.5 cm in diameter in the lower-inner quadrant of the right breast. Tumor markers such as CEA, CA153, BCA225 and NCC-ST-439 were within normal limits. Mammography showed two oval radioopaque masses with microcalcification in the smaller one. Ultrasonography disclosed two cysts and papillary projection in the larger one. Fine needle aspiration cytology revealed apocrine carcinoma of the breast. Excisional biopsy confirmed the diagnosis of apocrine carcinoma with focal invasion. Modified radical mastectomy was performed. Pathological study showed that the tumor mainly proliferated in the cysts and the two cysts communicated with each other through an involved duct. There was no apocrine metaplasia in adjacent mammary gland. There were no metastatic lymph nodes. This case may be regarded as intraductal apocrine carcinoma developing two cysts with focal invasion.