[A Case of Tubular Carcinoma of the Breast].

We report a case of tubular breast carcinoma discovered during an ultrasound examination during an opportunistic breast cancer screening. The patient was a 71-year-old woman. An ultrasound examination during an optional health check revealed a mass lesion in her left breast and she visited our department. Mammography revealed no abnormal findings. Ultrasonography revealed a hypoechoic mass measuring 5 mm in diameter in the AC area of the left breast. Core needle biopsy revealed tubular carcinoma. Systemic examination revealed no obvious distant metastasis. A circular lumpectomy and sentinel lymph node biopsy was performed. Histopathological findings showed tubular breast carcinoma, tumor diameter 7 mm, negative resection margins, and no lymph node metastasis. Ki-67 6.2%, ER positive, PgR positive, HER2 negative. After postoperative radiation therapy, the patient is being followed up with an aromatase inhibitor. One year after surgery, there has been no obvious metastasis or recurrence. Tubular carcinoma is pathologically characterized by a high amount of fibrous stroma surrounding the lumen, and ultrasound findings often show a hypoechoic mass with unclear boundaries and attenuation of posterior echoes. In this case, ultrasound examination was also useful in estimating the histological type.