[The difficulty of choosing a treatment strategy for ductal carcinoma in situ of the breast detected by breast cancer screening-a case report].

We report a case of ductal carcinoma in situ( DCIS) that was detected by breast cancer screening. A 42-year-old woman came to our department for follow-up evaluation of breast cancer. One year previously, she had undergone mammography, which showed amorphous and grouped calcifications in the UO area of her left breast. However, another doctor judged that the patient did not need to undergo biopsy as no tumor could be detected by ultrasonography. One year later, the patient returned for follow-up mammography. Mammography showed that the calcifications in the UO area of her left breast had increased. Vacuum-assisted core-needle biopsy was performed, and histopathological examination revealed DCIS of the breast. The tumor was estrogen receptor( ER) and progesterone receptor( PgR) positive with a human epidermal growth factor receptor( HER) 2 score of 1. Computed tomography( CT) and bone scintigraphy were performed and no metastasis to the brain, lungs, liver, bones, infraclavicular lymph nodes, or axillary lymph nodes was detected. Left breast cancer( Tis, N0, M0: Stage 0) was diagnosed, and left modified radical mastectomy and biopsy of sentinel lymph nodes were performed. According to the intraoperative rapid histopathological diagnosis, the sentinel lymph nodes were negative for metastasis and the final histopathological diagnosis was DCIS. It is difficult to decide whether to perform vacuum-assisted core-needle biopsy in a patient with microcalcifications. This case shows that we should not hesitate in obtaining biopsies of areas wherein the presence of calcification could cause us to question our diagnosis.