Metastatic Breast Carcinoma Presenting as Perforated Appendicitis.

SUMMARY: BACKGROUND: Patients presenting with symptoms from unknown metastatic breast carcinoma are becoming increasingly uncommon. Perforated appendicitis from metastatic breast carcinoma is a rare entity with only a few published reports in the literature. CASE REPORT: The case of a 76-year-old female patient who developed perforated appendicitis from previously unknown metastatic breast cancer is presented. During physical examination in the emergency department, a large left breast mass was palpated. The patient underwent an appendectomy and had no gross evidence of disease elsewhere in the intra-peritoneal cavity. Subsequent pathologic examination of the appendix revealed a lobular carcinoma. CONCLUSIONS: The factors that influence the site of metastasis from breast cancer include estrogen receptor status and the subtype of carcinoma - ductal versus lobular.