BACKGROUND - Breast cancer is the most commonly diagnosed cancer in pregnancy. Though the prognosis by stage is not different from that in nonpregnant women, it is more likely to present at an advanced stage in pregnancy.
CASE - A 28-year-old primigravida presented with dyspnea and pleuritic chest pain. The workup revealed cardiac tamponade. Pericardiocentesis and subsequent pericardial window were performed. Cytology of the pericardial fluid revealed poorly differentiated adenocarcinoma. Ultrasonography displayed a right breast mass, and biopsy identified it as the primary source of the cancer.
CONCLUSION - Cardiac tamponade is an unusual presentation of advanced breast cancer. To the best of our knowledge, it has not previously been described as occurring in pregnancy.