[A Case of Retroperitoneal Abscess Due to Acute Appendicitis during Neo-Adjuvant Chemotherapy for Breast Cancer].

When acute appendicitis occurs in patients treated with chemotherapy, neutropenia and abdominal complaints caused by chemotherapy can contribute to the diagnostic difficulty, masking the increase in white blood cell(WBC)counts and physical findings of acute appendicitis. A 43-year-old premenopausal woman who was diagnosed with stage IIIA left breast cancer was scheduled for neoadjuvant chemotherapy includingfluorouracil plus epirubicin plus cyclophosphamide(FEC), followed by docetaxel and trastuzumab(DOC plus HER). The patient developed fever and lower abdominal pain on day 17 of DOC plus HER cycle 1, and was diagnosed with acute gastroenteritis in the emergency room. These symptoms were almost improved 4 days later, and then cycle 2 was performed as scheduled. WBC counts decreased to 1,530 cells/mL due to DOCinduced myelosuppression on day 8 of cycle 2 when the patient developed lower abdominal pain again. However, WBC counts increased to 21,680 cells/mL on day 13 of cycle 2. Computed tomography scans revealed an intraperitoneal abscess due to acute appendicitis, and consequently urgent operation was performed. It is necessary to understand that patients with acute appendicitis duringchemotherapy can present less clinical findings.