A Case of Pure Type Mucinous Carcinoma Recurrence after Local Control

Abstract The patient was a 44-year-old woman. Mastectomy and sentinel lymph node biopsy had been performed for carcinoma of the left breast approximately 1 year previously. The diagnosis was mucinous carcinoma, T3N0M0, stage ⅡB, ER(+), PgR(+), HER2 score 0, Ki-67 20%. Hormone therapy was administered postoperatively. Four months after the surgery, left axilla lymphadenopathy was observed. Chemotherapy with EC and nab-PTX was started for the postoperative lymph node recurrence. To achieve local control, axillary lymphadenectomy was performed within 1 year postoperatively, and 1 metastatic lesion in the lymph nodes was observed. Hormone therapy was started sequentially, with no subsequent recurrence or metastasis. Mucinous carcinomas are classified as a breast cancer subtype. Mixed type, including breast ductal carcinoma, form a large proportion of mucinous carcinomas and the therapy for breast ductal carcinoma is usually administered in such cases. Conversely, pure type mucinous carcinomas rarely show metastasis and have a good prognosis. In this case, however, metastasis was noted and chemotherapy was not completely effective, and local control was achieved with surgical resection.