Pulmonary Dirofilariasis

Abstract

BILATERAL nodular "coin" densities of the lung usually denote metastatic neoplasm. Granuloma, pulmonary cysts, hamartoma, and collagen disease of the lung are less common causes of this roentgenographic expression. Recently, pulmonary arteriolar thrombosis by a parasitic helminth has been recognized as a further cause of the coin lesion. Nine cases of pulmonary nodular density produced byDirofilaria immitis, the common heartworm of dogs, have been reported from the United States, all within recent years. These cases and two others in whichD immitiswas found in the right side of the heart and associated vessels were summarized recently by Beaver and Orihel.¹ In all of the previously reported cases, the pulmonary lesions were solitary. In the case reported herein, there were similar densities, but bilateral. One of the coin lesions was resected and proved to be due to arteriolar occlusion byD immitis. The contralateral density, presumptively caused by