Primary peritoneal serous papillary carcinoma that metastasized to an axillary lymph node in a woman with a history of breast cancer: A case report and diagnostic pitfalls

Herein, we will report on a patient with primary peritoneal serous papillary carcinoma that metastasized to an axillary lymph node and who had previously undergone a mastectomy and chemotherapy for carcinoma of the right breast. A 40-year-old Japanese woman underwent partial resection of her left lung for metastatic breast cancer at our hospital. Thirteen years later, she developed a left axillary lymph node swelling, and a biopsy was performed. Histological findings were compatible with metastatic breast carcinoma. Positron emission tomography–computed tomography revealed systemic lymphadenopathy, peritoneal nodules, and a liver mass. The patient was diagnosed with recurrent breast cancer and underwent additional chemotherapy. Six months later, she developed ascites. She was diagnosed with serous adenocarcinoma using conventional and immunocytological examinations of the ascites. She underwent suboptimal debulking surgery, consisting of a total hysterectomy, bilateral oophorectomy, and partial omentectomy. The final pathological diagnosis was primary peritoneal serous papillary carcinoma.The diagnosis and pitfalls of this case will be presented.