Pulmonary dirofilariasis. The largest single-institution experience.

Pulmonary dirofilariasis caused by Dirofilaria immitis, the dog heartworm, is a rarely reported pulmonary lesion. It appears as a solitary pulmonary nodule, and the diagnosis is not established until thoracotomy and subsequent histologic examination of the specimen are performed. Sporadic reports of pulmonary dirofilariasis in the United States total only 70 cases. The six resections of pulmonary dirofilariasis at the Ochsner Clinic represent the largest reported series of cases originating at a single institution. We present an overview of the pathogenesis of this disease, its clinical manifestations, pathologic and epidemiologic features, and geographic distribution. The prevalence of pulmonary dirofilariasis appears to be increasing; hence, thoracic surgeons and pathologists need to be alert to this cause of granulomatous pulmonary lesions.