Bilateral Pulmonary Hydatid Cysts in An Adolescent: Histological Confirmation of The Left Cyst With Associated Chronic Inflammation: A Case Report

Abstract

Background: Histopathological examination establishes the nature of a pulmonary cystic lesion by demonstrating parasite-derived structures and characterising the surrounding tissue response.

Case presentation: A 16-year-old boy with exertional dyspnoea had bilateral pulmonary cystic lesions detected during investigations for right iliac fossa pain. CT showed a right air-containing lesion measuring 6.5 × 8.5 cm, suspicious for a ruptured hydatid cyst, and a thin-walled, fluid-attenuation left lower-lobe lesion measuring 7.4 × 7.7 cm. The left lesion was surgically removed. Gross examination demonstrated an 8 × 7.5 × 7.3 cm cyst with a thin, friable wall. Microscopically, an acellular laminated membrane and protoscolices with hooklets established the diagnosis of a hydatid cyst. Adjacent tissue showed reactive lymphoid follicles, eosinophilic inflammation and necrosis. No malignancy was identified. Albendazole was administered as adjunctive treatment, and satisfactory left lung expansion was described at discharge.

Conclusion: The combination of an acellular laminated membrane and protoscolices provided morphological confirmation of a pulmonary hydatid cyst. The associated inflammation represented a host tissue response but did not, by itself, establish cyst rupture or bacterial superinfection. Correlation with imaging defined the wider bilateral pulmonary presentation.