Pulmonary cystic echinococcosis over 20 years in a single centre: Differences with hepatic cystic echinococcosis.

INTRODUCTION: Pulmonary cystic echinococcosis, caused by Echinococcus spp., is a zoonotic parasitic disease characterized by hydatid cysts in the lungs. Because of pulmonary tissue elasticity, cysts may enlarge considerably before symptoms appear, often resulting in incidental diagnosis. Compared with hepatic cystic echinococcosis, pulmonary cystic echinococcosis poses distinct diagnostic and therapeutic challenges. This study analyzes a 27-year cohort to describe clinical features, management, and outcomes. METHODS: We performed a retrospective observational study of cases diagnosed between January 1998 and December 2024 at the Complejo Asistencial Universitario de Salamanca, identified through ICD-9 and ICD-10 codes. Of 709 confirmed cystic echinococcosis cases, 80 (11.3%) were pulmonary cystic echinococcosis. Patients were mainly middle-aged men from rural areas. Isolated pulmonary involvement was frequent, and nearly half developed mechanical complications such as rupture or compression. Serology was positive in most patients, while eosinophilia was uncommon. RESULTS: Treatment strategies included surgery alone, surgery plus albendazole, exclusive medical therapy, or watchful waiting; PAIR was rarely used. Postoperative morbidity was low. Seven patients died during follow-up, three from echinococcosis-related causes. CONCLUSIONS: Compared with hepatic disease, pulmonary cystic echinococcosis affected younger individuals, was more often symptomatic, had higher complication rates and greater serological positivity, but lower disease-specific mortality. These findings support early diagnosis, active treatment, structured follow-up, and targeted public health interventions in high-risk populations. Larger prospective studies are needed to optimize management strategies.