Acute appendicitis as an unusual cause of invasive ductal breast carcinoma metastasis

Acute appendicitis is one of the most common causes of abdominal pain at the emergency room. In rare cases, it can be caused by malignancy, even metastatic lesions from extra-abdominal neoplasia. Herein, we report a case of a 64-year-old female with a history of invasive ductal carcinoma of the breast treated by chemotherapy, surgery, radiotherapy and hormonotherapy, relapsing several years later as a bone and a pleura metastasis successfully cured by locoregional therapy and hormonal treatment. She presented with acute abdominal pain without signs of peritonitis. Abdominal computed tomodensitometry showed sign of appendicitis. Therefore, laparoscopic exploration and appendicectomy was performed. During surgery, multiple peritoneal nodules were found and harvested. Pathology showed metastatic nodules of invasive ductal breast carcinoma, including in the appendicular wall, concluding to peritoneal carcinomatosis. The postoperative course was uneventful, but the patient died 1 year later after refusing anticancer treatment.