Isolated Ruptured Pulmonary Hydatid Cyst Mimicking Community-Acquired Pneumonia.

Hydatid disease, most commonly caused by Echinococcus granulosus, usually affects the liver, and isolated pulmonary involvement is rare. Ruptured lung cysts can mimic pneumonia, often delaying diagnosis. Although surgery is the standard treatment, medical therapy alone has occasionally been successful. We report a 42-year-old healthy Lebanese man who presented with fever and elevated inflammatory markers suggestive of pneumonia that did not respond to broad-spectrum antibiotics. Imaging revealed right lower lobe consolidation accompanied by bilateral patchy ground-glass opacities. Additionally, there was a cavitary lesion with detached membranes in the right lower lobe, consistent with a ruptured pulmonary hydatid cyst. No liver involvement was noted. He was treated conservatively with albendazole and antibiotics, leading to rapid clinical and biochemical improvement. This case highlights the need to consider hydatid disease in endemic regions for non-resolving pneumonia and demonstrates the potential role of medical therapy alone in select patients.