Pulmonary dirofilariasis. The largest single-hospital experience

Pulmonary dirofilariasis caused by Dirofilaria immitis, the dog heartworm, is a rarely reported pulmonary lesion. It most often appears as a solitary pulmonary nodule, often mistaken for a primary or metastatic lung tumor, and the diagnosis is not often established until thoracotomy with excisional lung biopsy is performed. Sporadic reports of pulmonary dirofilariasis in the United States total only 87 cases. The ten resections of pulmonary dirofilariasis at the Methodist Hospital in Houston, Tex, represent the largest reported series of cases originating at a single hospital. We present an overview of the pathogenesis of this disease, its clinical manifestations and epidemiologic features. The prevalence of pulmonary dirofilariasis appears to be increasing. Thus, surgeons and pathologists need to be aware of this etiology of granulomatous pulmonary lesions.