Objective: The objective of our study was to describe the characteristic radiologic findings of pulmonary toxocariasis on initial and follow-up chest CT.
Materials and methods: Between June 2010 and May 2014, 63 patients with serologically proven, clinically diagnosed pulmonary toxocariasis and chest CT examinations performed within 2 months of an enzyme-linked immunosorbent assay for toxocariasis were identified. Two chest radiologists retrospectively analyzed the chest CT examinations in consensus; they focused on the distribution, location, number, and internal characteristics of the pulmonary lesions.
Results: The pulmonary lesions tended to involve three or more lobes (49% [31/63]) on the initial CT; predominance of the abnormalities in a subpleural location (81% [51/63]) and in the lower lung zone (98% [62/63]) was noted. The number of pulmonary lesions per patient were from two to five (46% [29/63]), more than five (32% [20/63]), or one (22% [14/63]). The radiologic findings of pulmonary toxocariasis could be categorized into four different patterns: ground-glass opacities (GGOs), solid nodules, consolidations, and linear opacities. The most common pattern was ill-defined GGOs with or without solid portions (84% [53/63]). The solid nodule and patchy consolidation patterns were found in 29% (18/63) and 21% (13/63) of patients, respectively. In addition, linear opacities (1-2 mm thick and 8-25 mm long) were present in 19% of patients (12/63); this finding is a subtle, yet novel, finding. On follow-up CT, the pulmonary lesions had either disappeared or migrated; when they had migrated, they revealed radiologic manifestations similar to the findings on the initial CT.
Conclusion: Pulmonary toxocariasis manifested as multiple lesions in four radiologic patterns with subpleural and lower lung predominance on initial and follow-up CT. A linear opacity may be one of many clues in the diagnosis of pulmonary toxocariasis on CT.
Keywords: chest CT; toxocariasis; visceral larva migrans.