Malignant Müllerian Adenocarcinoma Manifesting With Cardiac Tamponade and Pleural Effusion

A 54-year-old woman with a past medical history of untreated stage IV Müllerian adenocarcinoma presented for dyspnea. She was found to have a large right-sided pleural effusion through basic radiology and clinically improved after a CT-guided therapeutic thoracocentesis. However, the patient rapidly deteriorated shortly afterward. A broader workup that included echocardiography revealed a large pericardial effusion with tamponade physiology. The patient underwent an emergent pericardiocentesis, which briefly improved hemodynamics, but her clinical status kept declining until she eventually expired. Subsequent cytology of the pleural and pericardial fluid revealed malignant cells of Müllerian origin.