Nocardia cyriacigeorgica threatening an immunocompetent host; a rare case of paramediastinal abscess.

We describe a rare case of anterior paramediastnial abscess due to Nocardia cyriacigeorgica in an immunocompetent patient without pre-existing lung disease. High suspicious should be taken in those patients that failed to improve after first course of antibiotic therapy. Similarly, when suspected, isolation is crucial because of the variation in antibiotic susceptibilities among Nocardia spp. in order to provide adequate therapy to reduce associated comorbidities and mortality rate.