[A Case of Primary Poorly Differentiated/Small Cell Carcinoma of the Breast in a Patient with Von Recklinghausen's Disease].

We report a case of neuroendocrine carcinoma and poorly differentiated/small cell carcinoma ofthe breast in a patient with von Recklinghausen's disease. The patient was a 46-year-old woman who was diagnosed with von Recklinghausen's disease when she was 22 years old. She presented with left breast pain, and physical examination revealed a firm mass in the left breast. A core needle biopsy of the tumor revealed triple negative breast cancer with neuroendocrine features. We performed a simple mastectomy with lymph node dissection. We did not plan neoadjuvant chemotherapy because the tumor would be possibly inoperative if neoadjuvant chemotherapy was not effective for this neuroendocrine cancer. The tumor was diagnosed as a neuroendocrine carcinoma and poorly differentiated/small cell carcinoma. The patient was treated with CDDP and CPT- 11, which is a regimen often used to treat small cell lung cancer.