[A Case of Neuroendocrine Carcinoma with Long-Term Abnormal Nipple Discharge].

We diagnosed invasive breast ductal cancer in a 42-year-old woman. About 10 years previously, she noticed an abnormal nipple discharge, and core needle biopsy indicated intraductal papilloma of the breast. However, the secretion continued, and we performed core needle biopsy again, which suggested invasive breast ductal cancer. Ultrasonography showed a hypoechoic tumor and an irregular low echo area. Breast MRI showed cystography tuberculum in the whole left breast. Pathological findings indicated solid papillary carcinoma with neuroendocrine differentiation, T2N0M0, stage ⅡA, ER(+), PgR(+), HER2 0. In this case, although needle biopsy was performed, the patient's long-term course provided key insights into the diagnosis. Moreover, the long-term bloody discharge from the nipple was a pathognomonic finding of intraneural secretory breast cancer, and it seemed important to take this morbus into consideration and follow-up on it.