Human pulmonary dirofilariasis masquerading as a mass.

Pulmonary dirofilariasis, caused by Dirofilaria immitis, rarely affects humans and is usually asymptomatic, but may present as chest pain, cough, hemoptysis, wheezing, low-grade fever, and malaise. The dead and dying worms obstruct branches of the pulmonary artery, causing infarction and a granulomatous reaction. Coin lesions are apparent on radiography, raising concern of malignancy. Complete surgical excision is the treatment of choice and an anthelmintic can be administered if residual lesions are present or the patient is from an endemic area. We present two cases of pulmonary dirofilariasis presenting as coin lesions in the lung, which were clinically suggestive of malignancy.