Transdiaphragmatic rupture of a calcified hepatic hydatid cyst into the bronchial tree: CT findings of a bronchobiliary fistula.

Transdiaphragmatic rupture of hepatic hydatid cysts into the bronchial tree is a rare but severe complication that may mimic pulmonary infection. We report the case of a 61-year-old man who presented with fever, dyspnea, and right thoracic pain, with initial CT findings suggestive of pneumonia and pleural effusion. Despite antibiotic therapy and surgical drainage, clinical deterioration persisted. Bronchoscopy revealed biliary secretions, and thoracoabdominal CT demonstrated a calcified hepatic hydatid cyst communicating with the right lower lobe bronchial tree through a diaphragmatic defect, establishing the diagnosis of a bronchobiliary fistula. This case highlights the crucial role of thoracoabdominal CT in identifying the hepatic origin of refractory pulmonary disease and in demonstrating the fistulous tract, which is essential for surgical planning.