Pulmonary dirofilariasis: Computed tomography findings and correlation with pathologic features

Objective: The purpose of this study was to describe the computed tomography (CT) and pathologic features of 5 nodules of pulmonary dirofilariasis in 4 patients. Methods: Four patients with 5 nodules of pathologically confirmed pulmonary dirofilariasis who underwent CTwere enrolled, and the imaging interpretations were retrospectively compared with the histopathologic characteristics. Results: Three of the 4 patients had a solitary nodule, and the remaining patient had 2 nodules. All the nodules were distributed in the right lower lobe and were attached to the pleura. They were all round or oval in shape and ranged in size from 11 to 22 mm in largest diameter (mean = 17 mm). On thinner section CT, the nodules had a well-defined smooth margin with or without a shallow notch; they were connected to the arterial branch and, occasionally, to the venous branch. On contrast-enhanced CT, all the nodules contained a homogeneous low-attenuation area, which corresponded to areas of coagulative necrosis on histopathologic examination. Conclusion: Although the CT findings of a pulmonary dirofilariasis nodule are nonspecific, awareness of the findings on contrast-enhanced CT and the pathologic appearance of this rare benign condition may facilitate its differentiation from a malignant nodule.