A Diagnostic Masquerader in a Tuberculosis-Endemic Region: A Case of an Isolated Complicated Pulmonary Hydatid Cyst in an Adolescent

Pulmonary hydatid disease, caused by <i>Echinococcus granulosus</i>, remains an underrecognized etiology of chronic respiratory symptoms in endemic regions, particularly when classical exposure history is absent. We describe the case of a 15-year-old adolescent girl from rural India who presented with a one-year history of progressive cough and intermittent hemoptysis, refractory to empirical antibiotic therapy. Imaging revealed a well-defined cystic lesion in the left upper lobe, and contrast-enhanced computed tomography (CECT) demonstrated the coexistence of crescent and water-lily signs, indicating a complicated pulmonary hydatid cyst with impending rupture. Serological testing for <i>Echinococcus granulosus</i> IgG was positive, while extensive evaluation for tuberculosis and fungal infections was negative, and no hepatic or extrapulmonary cysts were identified. The patient was treated with preoperative albendazole followed by successful lung-preserving surgical enucleation, resulting in complete clinical and radiological recovery without recurrence. This case underscores the diagnostic value of characteristic imaging findings and highlights the necessity of considering pulmonary hydatid disease in adolescents with persistent respiratory symptoms in tuberculosis-endemic settings, even in the absence of identifiable zoonotic exposure.