[Pulmonary nocardiosis with cerebral abscesses mimicking metastatic lung cancer: Three cases and a review of literature].

Nocardiosis is an infectious disease with wide range of clinical features, which can eventually lead to death. The agent responsible belongs to the genus Nocardia that includes about fifty different species. Nocardiosis occurs mainly in immunocompromised hosts. We report here three cases of disseminated nocardiosis misdiagnosed initially as cerebral metastatic lung cancer. These patients, including two immunocompetent hosts, presented with both pulmonary and cerebral lesions. In all three patients, the diagnosis was based on magnetic resonance imaging with diffusion sequence, apparent diffusion coefficient reconstruction and neurosurgical cerebral biopsies. Treatment with an appropriate antibiotic regimen was prolonged for several months. Progress was favorable with full resolution of the neurological symptoms and the radiological abnormalities. These three cases emphasize the diagnostic challenge of nocardiosis, especially in disseminated disease.