A rare case of human pulmonary dirofilariasis with nodules mimicking malignancy: approach to diagnosis and treatment.

BACKGROUND: Human pulmonary dirofilariasis is a rare zoonosis caused by the dog worm Dirofilaria spp., a parasite transmitted by mosquitos and resulting in peripheral lung nodules. The filarial nematode enters the subcutaneous tissue, travels to the right ventricle and dies causing a small pulmonary infarction that may embolize through the pulmonary vessels and may appear as a solitary nodule. These nodules are usually incidentally identified in asymptomatic patients undergoing chest imaging studies, and are generally interpreted to be malignant. CASE PRESENTATION: We present the case report of a human dirofilariasis in a patient with multiple pulmonary nodules resected using video-assisted thoracic surgery (VATS). According to our literature review, this is the first case with double synchronous lung nodules reported in Italy. CONCLUSIONS: Minimally invasive resection with histologic examination may be the best approach for the diagnosis and treatment of pulmonary dirofilariasis. Polymerase Chain Reaction testing may provide a more accurate etiological diagnosis in case of an inconclusive pathology result.

Tomographic findings of acute pulmonary toxoplasmosis in immunocompetent patients.

BACKGROUND: Toxoplasmosis is one of the most common human zoonosis, and is generally benign in most of the individuals. Pulmonary involvement is common in immunocompromised subjects, but very rare in immunocompetents and there are scarce reports of tomographic findings in the literature. The aim of the study is to describe three immunocompetent patients diagnosed with acute pulmonary toxoplasmosis and their respective thoracic tomographic findings. Acute toxoplasmosis was diagnosed according to the results of serological tests suggestive of recent primary infection and the absence of an alternative etiology. CASE PRESENTATION: From 2009 to 2013, three patients were diagnosed with acute respiratory failure secondary to acute toxoplasmosis. The patients were two female and one male, and were 38, 56 and 36 years old. Similarly they presented a two-week febrile illness and progressive dyspnea before admission. Laboratory tests demonstrated lymphocytosis, slight changes in liver enzymes and high inflammatory markers. Tomographic findings were bilateral smooth septal and peribronchovascular thickening (100%), ground-glass opacities (100%), atelectasis (33%), random nodules (33%), lymph node enlargement (33%) and pleural effusion (66%). All the patients improved their symptoms after treatment, and complete resolution of tomographic findings were found in the followup. CONCLUSION: These cases provide a unique description of the presentation and evolution of pulmonary tomographic manifestations of toxoplasmosis in immunocompetent patients. Toxoplasma pneumonia manifests with fever, dyspnea and a non-productive cough that may result in respiratory failure. In animal models, changes were described as interstitial pneumonitis with focal infiltrates of neutrophils that can finally evolve into a pattern of diffuse alveolar damage with focal necrosis. The tomographic findings are characterized as ground glass opacities, smooth septal and marked peribronchovascular thickening; and may mimic pulmonary congestion, lymphangitis, atypical pneumonia and pneumocystosis. This is the largest series of CT findings of acute toxoplasmosis in immunocompetent hosts, and the diagnosis should be considered as patients that present with acute respiratory failure in the context of a subacute febrile illness with bilateral and diffuse interstitial infiltrates with marked peribronchovascular thickening. If promptly treated, pulmonary toxoplasmosis can result in complete clinical and radiological recovery in immunocompetent hosts.