An unexpected zoonosis: pulmonary dirofilaria infection mimicking pulmonary neoplasm

Abstract

Pulmonary dirofilaria infection is a rare condition in Australasia. We describe a case with radiographic findings concerning for pulmonary malignancy, with the unexpected pathological diagnosis of dirofilarial infection.

Human pulmonary dirofilariasis: an unexpected differential diagnosis for a solitary lung lesion

“…Malignancy is frequently suspected, although fine needle biopsy is typically non‐diagnostic 7 . Diagnosis is generally made on histological specimen following surgical resection 1,3 . Serological testing is not validated in isolation but may be complementary to diagnostic workup 1,3 .…”

“…The pulmonary nodule is typically described as a “coin lesion” frequently located within the right lower lobe 1,4 . Patients are commonly asymptomatic, but haemoptysis, chest pain, fever and eosinophilia can occur 1,3 . Varying 18 F‐FDG avidity has been reported in cases of human pulmonary dirofilariasis, ranging from non‐avid to an SUV of 7.5 4‐6 .…”

“…Hence, no antihelminthic therapy is required 1 . Where surgery has occurred, resection is considered definitive 1,3 …”

“…Mosquitos are vectors for D. immitis , hence its prevalence in tropical and subtropical climates 2 . Definitive hosts include various mammals, frequently domestic and wild dogs 1,3 . Humans are considered incidental hosts following inoculation of larvae via an infected mosquito 3 .…”

“…Definitive hosts include various mammals, frequently domestic and wild dogs 1,3 . Humans are considered incidental hosts following inoculation of larvae via an infected mosquito 3 . The larvae enter the pulmonary vasculature and embolise into smaller peripheral arterial branches 2 .…”