A Case of Right Breast Cancer Diagnosed with Malignant Adenomyoepithelioma after Resection of the Metastases

Abstract

A 56-year-old woman who was diagnosed with right breast cancer underwent total mastectomy along with sentinel lymph node biopsy. Pathological diagnosis included invasive ductal carcinoma (papillotubular), NG3, ER(-), PgR(-), Ki-67=20%, HER2(-) ; pT1b (9 mm), pN0, M0 ; Stage I, with an adjacent adenomyoepithelioma. The patient was followed up without adjuvant therapy. Four years after the operation, computed tomography (CT) scan showed a lobular and multinodular tumor in Segment 6 of the right lung. Four months later, a thoracoscopic right lower lobectomy of the lung was performed at another hospital, where a tumor with proliferating myoepithelial cells was detected. Pathological review led to the diagnosis of malignant adenomyoepithelioma. It was noted that both the ductal and myoepithelial components were malignant, measuring approximately 20 mm. Four courses of epirubicin cyclophosphamide (EC), followed by 12 courses of weekly paclitaxel (weekly PTX) were administered as postoperative adjuvant chemotherapy. Following this treatment, the patient developed multiple distant metastases in the brain, lung, liver, and kidney. The patient's general condition deteriorated due to progression of the distant metastases. The patient is currently undergoing follow-up with best supportive care and Palliative care at home.