Ruptured Pericardial Hydatid Cyst Causing Mitral Annulus Distortion With Severe Mitral Regurgitation and Tamponade-like Symptoms: A Case Report.

BACKGROUND Hydatid disease, a parasitic zoonotic infection caused by Echinococcus granulosus, is characterized by the formation of cysts in various organs. Transmission occurs via the fecal-oral route. The disease is endemic in regions where livestock farming is common, including rural areas of the Mediterranean, Africa, the Middle East, and South America. The liver and lungs are the most commonly affected organs, with reported involvement rates of 50% to 70% and 20% to 30%, respectively. In rare cases, cardiac involvement occurs (0.5%-2%), most frequently affecting the left ventricle due to its rich blood supply. Cysts may occur in any cardiac location; however, pericardial involvement is particularly uncommon, representing approximately 7% of cardiac cases. CASE REPORT A 42-year-old man from an endemic region developed sudden chest discomfort, severe dyspnea, hypotension, and orthopnea. Clinical examination revealed findings consistent with cardiac tamponade and pulmonary edema. Imaging studies demonstrated a ruptured pericardial hydatid cyst; multiple floating daughter cysts were evident within the pericardial sac. The patient underwent cystectomy followed by mitral valve replacement and received postoperative albendazole therapy. Recovery was uneventful, and the patient remained asymptomatic at the 12-month follow-up. CONCLUSIONS Rupture of a pericardial hydatid cyst, although rare, should be considered in the differential diagnosis of cardiac tamponade and pulmonary edema, particularly in endemic regions. Early diagnosis and combined surgical and medical management are essential to achieve favorable outcomes.