Background: The dog heartworm Dirofilaria immitis is known to cause solitary pulmonary nodules in humans. Human pulmonary dirofilariasis (HPD) is more prevalent along the coastal regions of the United States, especially along the Mississippi River Valley. Diagnosis is generally made by surgical resection, since HPD is often preoperatively presumed to be lung cancer.
Methods: I searched for relevant clinical articles and case reports on HPD, using MEDLINE and the Index Medicus. I carefully reviewed each article for information regarding HPD.
Results: Of the 37 cases reviewed, 29 (78.4%) were in the southern and southeastern states. The youngest patient was a 33-year-old woman, and the oldest was a 79-year-old man (mean age, 57.3 years). This literature review found that 43.2% were symptomatic, 51.4% were asymptomatic, and 5.4% were not recorded. Solitary lesions were found in 89.7%, with a mean diameter of 1.9 cm.
Conclusion: Based on the available literature and epidemiologic data, HPD should be considered in the differential diagnosis of pulmonary nodules in the appropriate clinical and geographic setting.