Pseudo–heart failure in pregnancy complicated by preeclampsia: giant mediastinal teratoma with extrinsic cardiopulmonary compression

A woman in her early 20s at 30 weeks of gestation presented with elevated blood pressure, transaminitis, progressive dyspnoea, orthopnoea, exertional chest pain and peripheral oedema, raising concern for preeclampsia-associated cardiopulmonary disease or peripartum cardiomyopathy. Transthoracic echocardiography showed preserved left ventricular systolic function, normal left-sided filling pressures, right ventricular dilatation and an estimated right atrial pressure of 15 mmHg; N-terminal pro-brain natriuretic peptide was 57 pg/mL. Cross-sectional imaging revealed a large multi-cystic anterior mediastinal mass occupying the left hemithorax, displacing the heart and abutting/compressing major cardiopulmonary structures. Labour was induced at 34 weeks after clinical stabilisation. Three months postpartum, the patient re-presented with worsening dyspnoea and haemoptysis and underwent complete surgical resection. Pathology confirmed mature cystic teratoma and cardiopulmonary symptoms resolved after resection.