A case of duplicated cancer simultaneously causing breast and endometrial cancer

Recently, with the increase in the number of young cancer patients, we often encounter multiple primary cancer (MPC). In MPC, careful examination is necessary because the treatment order and policies change greatly depending on the stage and prognosis of each tumor. We report a case of synchronous MPC of endometrial cancer and breast cancer. The patient was a 40-year-old woman who underwent endometrial cytology by a previous doctor due to illicit bleeding. As a result of the diagnosis of class III B, she underwent gynecological examination in our hospital. Endometroid adenocarcinoma Grade 2 was diagnosed based on endoscopic findings. On pelvic MRI, a lesion adjacent to the neck showed a low signal in the uterine body compared to that in the endocardium. During the preoperative examination, CT showed contrast nodules in the right breast, and ultrasonography was performed at the department of breast surgery. Ultrasonography showed a low-echo mass of 23 mm in the right upper midline region. The needle biopsy results were papillotubular cancer (ER-negative, PgR-negative, HER2 1+, Ki-67 77%). Based on these findings, right breast cancer and endometrial cancer were diagnosed. Initially, we performed right mastectomy and sentinel lymph node biopsy; we then performed pancreatectomy in the gynecology department 2 weeks after discharge. After surgery, gynecology studied 6 courses of TC therapy, and currently, EC is undergoing breast surgery.