A case of pulmonary dirofilariasis showing accumulation on FDG-PET

Abstract

The patient was a 63-year-old woman. An abnormal shadow on X-ray films was noted. Chest computed tomography revealed a 2 cm nodular shadow with an irregular margin and cavity, and F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) showed accumulation in the nodule. We suspected primary or metastatic lung cancer, and therefore, partial resection of the lung was performed to diagnose and treat the tumor. The pathologic sample revealed Dirofilaria immitis. It is difficult to differentiate lung cancer from pulmonary dirofilariasis because pulmonary dirofilariasis often shows CT findings similar to lung cancer and is false-positive on FDG-PET. Pulmonary dirofilariasis must be kept in mind as a probable diagnosis when an abnormal shadow is observed in the lung.