A Case Strongly Suspected of Being Pulmonary Toxocariasis Showing Multiple Pulmonary Nodules with a Disappearing and Reappearing Halo Sign

Abstract

We report herein on a case strongly suspected of being pulmonary toxocariasis. A 22-year-old Indonesian man referred to our hospital presented with abnormal chest shadows upon medical examination. He had no symptoms. He did not have any pets nor did he eat raw beef or chicken. Hematological examination revealed eosinophilia and elevation of IgE. Chest computed tomography revealed 3 pulmonary nodules with the halo sign. We suspected a parasite infection and performed antiparasite antibody testing. Ascaris suum was slightly positive on the screening test. As specific antibody against the larval excretory-secretory products of Toxocara canis, measured at the National Institute of Infectious Diseases, was positive (level 3 up to 8). Subsequently, the abnormal chest shadows disappeared. However, two months later, 2 pulmonary nodules with the halo sign reappeared in other places. Diagnostic therapy with albendazole was performed for 8 weeks. Mild hepatic impairment emerged during therapy, but it was within the allowed range. Thereafter, the results improved for the imaging findings, eosinophilia, serum IgE level, and specific antibody. The antibody level became negative two months after the treatment had ended. We should consider toxocariasis in the differential diagnosis of migratory nodular shadows with the halo sign on chest computed tomography, and immunoserological testing is useful for the diagnosis.