Pulmonary Hydatid Cyst Mimicking Both Tuberculous Cavity and Aspergilloma: A Diagnostic Challenge in an Endemic Region.

Cystic echinococcosis (CE), caused by Echinococcus granulosus, is a zoonotic disease endemic in many pastoral regions. Pulmonary involvement, although less common than hepatic, may present with nonspecific respiratory symptoms and mimic other pathologies such as tuberculosis, posing a diagnostic challenge. We report a case of a 17-year-old Arab female from an endemic area who presented with cough, hemoptysis, fever, and general malaise. Chest imaging revealed a cavitary lesion in the upper lobe, raising suspicion of pulmonary tuberculosis or fungal infection. Laboratory findings showed leukocytosis and elevated inflammatory markers. Bronchoscopy and microbiological workup were negative for TB and fungi, though Klebsiella was cultured. Despite initial improvement with antibiotics, the definitive diagnosis was established intraoperatively after surgical resection revealed a complicated hydatid cyst. Postoperative culture identified Pseudomonas, and histopathology confirmed hydatid disease. This case highlights the diagnostic difficulty of pulmonary CE, particularly when imaging mimics tuberculosis. The upper lobe location and cavitary appearance contributed to initial misdirection. A lack of response to empirical therapy should prompt reconsideration of differential diagnoses, especially in endemic regions. Pulmonary hydatid cysts may present atypically and resemble more prevalent conditions like tuberculosis. Clinical vigilance, especially in endemic areas, is critical for timely diagnosis and appropriate management.