Pulmonary Sparganosis: Tunnel Sign and Migrating Sign on Computed Tomography

A 77-year-old woman presented at our hospital to undergo a close examination of an abnormal shadow which was observed on a chest radiograph. Contrast-enhanced computed tomography (CT) images in the lung window revealed a tortuous tunnel structure (tunnel sign), which was suspected to be the migration path of a parasite. Furthermore, CT images in the mediastinal window showed a linear filling defect from the right inferior pulmonary vein to the venous ostium in the left atrium (migrating sign), which was suspected to be a migrating parasite in the pulmonary vein. Tunnel and migrating signs on chest CT images were helpful in diagnosing pulmonary sparganosis.