A case of large cell neuroendocrine carcinoma originating from the breast in a male

Abstract

A 66-year-old male noticed a left breast tumor. Mammography and ultrasonography revealed a 20-mm-diameter mass in the left mammary gland (area C). Fine needle aspiration cytology and core needle biopsy results suggested the possibility of malignancy. Based on immunohistochemical staining the tumor was diagnosed as a carcinoid tumor or a neuroendocrine carcinoma. Estrogen and HER2 receptors were positive, PgR receptor testing was negative. A modified radical mastectomy with axillary lymph node dissection was performed. On histology a large cell neuroendocrine carcinoma (LCNEC) was diagnosed. Lymph node metastases were not found. Subseguently, the patient received adjuvant chemotherapy (EC) ; Letrozole administration is ongoing. To date the patient is without recurrence for one year and eleven months. Male breast cancer and LCNEC are rare. In particular only six cases including our case of LCNEC have been reported in Japan. The 6 cases were reviewed to evaluate their therapeutic outcomes so as to establish a prognosis for this disease entity.